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Thread: Does anyone have (or know where to see) samples of IQ180 at F/22?

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    Jim2
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    Does anyone have (or know where to see) samples of IQ180 at F/22?

    I'm curious to see comparison of images shot at F/22 on P65+ vs IQ180. Would like to see it on P65+ if that's all you have. Thank you very much!

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jim2 View Post
    I'm curious to see comparison of images shot at F/22 on P65+ vs IQ180. Would like to see it on P65+ if that's all you have. Thank you very much!
    It will be hard to find someone who has done this comparison because at f/22 both systems will be equally (very) soft. Both are well past their diffraction limit by f/16.5 and by f/22 are going to be mushy soft.

    It would be like asking for a comparison of the P65+ vs. the IQ180 handheld at 2 seconds. Both will look awful, so why do the comparison?

    See the diffraction test here:
    http://www.captureintegration.com/tests/phase-one/

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    I'm with Doug i would not even think of shooting at F22 so all my images with the IQ 180 which are a lot none of them is at those apertures. F16 really is about the max with any MF lens in any brand to be honest.
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Guy Mancuso View Post
    I'm with Doug i would not even think of shooting at F22 so all my images with the IQ 180 which are a lot none of them is at those apertures. F16 really is about the max with any MF lens in any brand to be honest.
    Alpa recommends F8 - F11 max with the majority of their newer lenses.

    Bob

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Yes and most of the Phase glass it is F11 at there best and some at F8. I rarely go to F16. I have seen diffraction at F16 on several lenses
    Photography is all about experimentation and without it you will never learn art.

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  6. #6
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Thanks for that link, Doug. Pardon my ignorance, but is it fair to say that IQ180 has a smaller diffraction limit i.e. that it needs bigger aperture opening than IQ160 due to its smaller pixel size (5.2u vs 6u) ?

    Does it stand to reason that a back with a bigger pixel size (say, P30+ or P2x) will have a diffraction limit at a smaller size aperture, meaning that they will remain sharp(ish) at F/18 for example, in comparison to IQ160 (or P65+ for that matter)?

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    Senior Member malmac's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Hi Jim2

    I understand the art of asking the wrong question - it is easy to do when moving into a new endeavour - as I suspect you are.

    Well I took my first photo with my new P65+ yesterday using the 55mm f2.8 Schneider LS lens at 100 iso, f11 @ 1/160. No sharpening in Capture One, no anything in Capture One, small increase in contrast in CS4.

    Sorry can't give you a comparison image from IQ180.

    But I can share my purchase decision. I have ordered an IQ160 instead of the IQ180 and spent the money I saved buying a Cambo WDS with a 35mm lens.
    If you want me to send you a full image from the P65+ just ask. I know how hard the decision is - which brand? Which camera? Is the image quality as good as people say? Couldn't I just stitch images from my Canon or Nikon and get the same resolution? and so on.

    It took me 18 months to make those decisions and I have only had one day to decide if I made the right decision.


    Cheers


    mal from www.malmac.net





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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    In general it is true that as you increase the pixel resolution/smaller sensor pitch, you'll end up seeing diffraction come in at wider apertures. With larger sensor pitch you'll see it kick in at slightly higher f stops.

    I could see some lenses on 80mp sensors hitting diffraction at f/5.6 or f/8 vs f/8 or f/11 that you'll often see today. It's not limited to MF either - the same is true with cameras like the D3x too.
    Remember: adventure before dementia!

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  9. #9
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by malmac View Post
    I understand the art of asking the wrong question - it is easy to do when moving into a new endeavour - as I suspect you are.
    Yeah I'm not an MFDB owner so I can't really play around with it to know. I want to know the F/22 answer because it will be what I plan to shoot with the most. On my Canon F/22 is definitely softer but acceptable for landscape photography.

    Quote Originally Posted by malmac View Post
    Well I took my first photo with my new P65+ yesterday using the 55mm f2.8 Schneider LS lens at 100 iso, f11 @ 1/160. No sharpening in Capture One, no anything in Capture One, small increase in contrast in CS4.
    Thanks for the sample image. Much appreciated! I know there's no sharpening done here, but I can't help to think that it looks very soft. Was it handheld or was it on a sturdy Tripod/head with MLU? Was there a focusing micro offset (i.e. the focus plane isn't perfectly aligned) that you're aware of? Did you use the Phase body (SLR) or Cambo? Or is the softness normal and will become 'properly' sharp once sharpened?

    Sorry with all the questions a bit excited to see I wonder if you can try to get the F/11 as sharp as possible and compare against F/22. Even shooting something inside is ok as long as it's on tripod with MLU. I just did this experiment with my Canon an hour ago

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jim2 View Post
    ... I can't help to think that it looks very soft.
    I would agree...looks like the focal plane is a good 6 - 12 inches in front of this building...the vertical 1x6 (2x6) near the peak seems to be sharper at its near edge than the rest.


    Bob

  11. #11
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by docmoore View Post
    I would agree...looks like the focal plane is a good 6 - 12 inches in front of this building...the vertical 1x6 (2x6) near the peak seems to be sharper at its near edge than the rest.


    Bob
    Is the DoF at F/11 that unforgiving (aka shallow)?

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Depends upon the focal length and the distance to the subject....a 24, 36, 45 will show great DOF at medium to long distances like landscapes...just look at Guy's recent workshop photos.

    The closer you get to the subject and the longer the focal length the more shallow the apparent DOF...this can be used to your advantage.

    Focus stacking can overcome this to a degree with static subjects...but one of the great advantages of MF is the shallow DOF ...use it you your advantage.

    Again diffraction limits our ability to compensate for the limited DOF but short focal length and longer distances give you huge areas that are "sharp enough."

    Bob

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    I agree with Doug and Guy. With the P65+ diffraction is easily observed at f22, though it's acceptable for small prints (say 16 by 20) - but why use a MFDB for small prints?

    F16 is generally OK but I do try to stay at f11. All of which means that when I've recovered from buying the IQ180, I'll be seeking a camera with tilt/swings to get the dof I need.

    What goes around comes around - it will be like going back to my 4 by 5 days!

    Bill

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    Workshop Member Wayne Fox's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jim2 View Post

    Sorry with all the questions a bit excited to see I wonder if you can try to get the F/11 as sharp as possible and compare against F/22. Even shooting something inside is ok as long as it's on tripod with MLU. I just did this experiment with my Canon an hour ago
    Seems the link Doug posted had good examples of what you are asking. the difference between f/16 and f/22 was pretty pronounced.

    Are you wanting to shoot mainly at f/22 for depth of field? I'm not sure any camera/lens can deliver that without running into diffraction issues.

    I think diffraction is a property of the lens, what changes is the ability of the sensor to resolve the detail. There isn't any more diffraction happening, just the sensor has the ability to actually record it.

    Of course, if you shoot with a IQ180 and downrez to the size of a IQ160 I'm guessing the end results will be virtually identical, meaning when you can shoot at 8 or 11 you get the best, but if you have to shoot at 22 there are options to deliver pretty much the same quality as the IQ160 at the same f/stop. Other post processing tools can reduce the visual effect of diffraction, especially when the object is printing the image large. Don't really want to stir up a big debate here, but I've used f/22 on more than one occasion and printed very large prints that look great.
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Wayne Fox View Post
    I think diffraction is a property of the lens, what changes is the ability of the sensor to resolve the detail. There isn't any more diffraction happening, just the sensor has the ability to actually record it.

    Of course, if you shoot with a IQ180 and downrez to the size of a IQ160 I'm guessing the end results will be virtually identical, meaning when you can shoot at 8 or 11 you get the best, but if you have to shoot at 22 there are options to deliver pretty much the same quality as the IQ160 at the same f/stop. Other post processing tools can reduce the visual effect of diffraction, especially when the object is printing the image large. Don't really want to stir up a big debate here, but I've used f/22 on more than one occasion and printed very large prints that look great.
    This is spot on.

    Basically the source of most confusion about confusion comes from comparing/judging images based soley on a 100% pixel view.

    If you view a 16mp image at 100% and it's tact sharp, and the view an 80mp image of the same scene at 100% and it's slightly soft you would conclude the 16mp image is sharp and the 80mp is soft. But if you made a 20x30 from both files the print from the 80mp image would show more detail.

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    The amount of energy diffracted is linearly proportional to fstop/f where f is the focal length. A 200 at f/22 will diffract about the same amount of energy as a 55 at f/5.6, and a 500/5.6 will diffract 1/10th that of the 55. There's an optimal crossover point between stopping down for DoF improving overall image sharpness (capture entropy), and it reducing sharpness due to diffraction. Factored, this crossover point actually is independent of focal length, and can be expressed in a simple table (if scale on lens says F, then use F') that's purely dependent on the circle of confusion used to produce the original lens DoF scale. I haven't found a single case the last 8 years when I started trying, then completely relying on this, where a simple table has been suboptimial. (See http://www.kenrockwell.com/tech/focus.htm; just ignore the random babble - the technical foundation is sound.)

    At some point for some shots it's impossible to get sufficient DoF without say shooting a 55 at f/22. The correct response is to rethink what you want in the image, whether there is an alternate composition based on layered focus, or whether some parts of it can be omitted to permit adequate DoF. The other consideration is if you can recompose for a smaller print (by enlarging the main point of interest - the visual anchor if you will). If it's borderline I say the shot is fine, just stop down for DoF, but as you stop down diffraction grows exponentially, so the image you get will deteriorate quickly if it's much past borderline.

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    Senior Member malmac's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Thanks for the sample image. Much appreciated! I know there's no sharpening done here, but I can't help to think that it looks very soft. Was it handheld or was it on a sturdy Tripod/head with MLU? Was there a focusing micro offset (i.e. the focus plane isn't perfectly aligned) that you're aware of? Did you use the Phase body (SLR) or Cambo? Or is the softness normal and will become 'properly' sharp once sharpened?

    Sorry with all the questions a bit excited to see I wonder if you can try to get the F/11 as sharp as possible and compare against F/22. Even shooting something inside is ok as long as it's on tripod with MLU. I just did this experiment with my Canon an hour ago
    Jim2

    I went back out to rephotograph the shed that I put up yesterday.

    Here is a composite image I made when using the 55mm Schnieder lens. On sturdy tripod, no wind, mirror up with a four second delay using the timer.

    As you can see I have included a crop and then a crop of a crop. I am not sure if people consider this to be as sharp as one might expect from this lens or is there some room for improvement?

    I guess I was surprised at how little difference there was in sharpness between wide open and f22.

    mal



  18. #18
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    I don't know how sharp an unsharpened image should look like... but Mal, all these shots look very soft to me, even the supposedly sharp F11.

    This was my experience with the DF body too - none of my images appear sharp. Is this what it is supposed to be? Maybe there are some slight alignment issues - which is what Mark Dubovoy always talks about in relation to shimming (even though he talks about Alpa most likely the sensor mis-alignment due to various reasons also occur on the DF body)?

    PS thanks for doing the re-take of the photographs at various F stops!

  19. #19
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Mal, I'm not sure if this is something you want to do (for fun!)

    - Capture tethered (to save time)
    - Set to AF at the barn area that we are looking at 100% crop
    - Take a shot - check shot result
    - Then switch lens to manual focus and adjust focus forward, take a shot, adjust focus back, take another shot

    See whether the AF is really doing its job properly?

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Looks like to me the AF nailed the foreground grass and not the wall. Little trick here focus on the wall with AF than switch the lens to manual than recompose. Your AF point looks to be getting confused between the grass and the wall as it is sitting mostly on the grass. This should be sharper. The 55mm LS is very good in the center for sure
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    jcoffin
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Even though I agree that the wall itself looks a bit OOF, I think the vertical board slightly left of center is pretty telling. If you look in the f/11 section, it has quite a well-defined surface texture. There's only a little of it showing in the f/16 section, so it's hard to say for sure, but I'd say it looks decidedly softer. In the f/22 section, we get only a hint of the surface being rough at all -- where the f/11 section shows clear saw marks, the f/22 section looks like somebody spent some time sanding it, so even though there's a bit of "waviness", there's no real texture left.

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    Senior Member kdphotography's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Wwwhat? No brick wall?

    I'm with Wayne and Doug here. Sometimes you let yourself get a bit antsy or worked up from pixel peeping too much, and perceived softness particularly with higher res backs. Yes, you still need to use good photography care in capture, but you'd be amazed how well those images print up....

    ken

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    Senior Member Steve Hendrix's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jim2 View Post
    Yeah I'm not an MFDB owner so I can't really play around with it to know. I want to know the F/22 answer because it will be what I plan to shoot with the most. On my Canon F/22 is definitely softer but acceptable for landscape photography.

    Thanks for the sample image. Much appreciated! I know there's no sharpening done here, but I can't help to think that it looks very soft. Was it handheld or was it on a sturdy Tripod/head with MLU? Was there a focusing micro offset (i.e. the focus plane isn't perfectly aligned) that you're aware of? Did you use the Phase body (SLR) or Cambo? Or is the softness normal and will become 'properly' sharp once sharpened?

    Sorry with all the questions a bit excited to see I wonder if you can try to get the F/11 as sharp as possible and compare against F/22. Even shooting something inside is ok as long as it's on tripod with MLU. I just did this experiment with my Canon an hour ago

    I think if you've been satisfied with the Canon images at f22, you'll probably be ok with IQ160 or IQ180 images at f22. Shooting at f22 isn't necessarily a deal killer, it typically has the effect of the loss of critical crunch, rather than being totally soft, if it is a sharp lens whose optical resolution is not overly weighted in the wider apertures.

    In my experience, there are definitely optical designs that favor the resolution that is captured at the wider end of the aperture range (and vice versa). So, that can play a role also.

    All that said, the question in my mind is what you shoot that most of your images require f22? Whatever it is, my assumption is that you are aiming for maximizing your depth of field? If so, perhaps there are workarounds that can produce a sharper image (if that is your objective) at a more optimal aperture. This is frequently a consideration when we discuss camera/lens choices with clients who are trying to maximize depth of field.

    The goal, in terms of the equipment, is often to try and move the target aperture to say, f11, and configure everything so that is possible and still attain an equivalent depth of field. Of course, there are limitations to this, but limitations don't always stop photographers from achieving their objective, do they? One advantage of a high resolution sensor is the ability to shoot at different distances and still end up with a high resolution image.

    To me, the critical sharpness (crunchiness) is lost (or begun) with almost all professional camera/lens combinations at f22. So, the effort is most often pointed towards - what can we do to get away with f16, or f11, etc.


    *Edit - Ken makes an important point here also, that we can get hung up looking at the image on the computer monitor/display and often, in terms of noise and sharpness, the print is quite different (usually in your favor).


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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Wayne Fox View Post
    the difference between f/16 and f/22 was pretty pronounced.
    It is. And when we did our IQ 180 test, I took one shot at f16 with the 55LS, and the negative aspects from diffraction are clearly visible at 100% view as compared to f11; f22 would be significantly worse. However that said, IMHO a print made from that f16 capture would pass most close scrutiny, and the slight amount of added DoF is probably more beneficial than the slight loss of fine detail. However, f22 would probably go the other way...
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    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jack Flesher View Post
    It is. And when we did our IQ 180 test, I took one shot at f16 with the 55LS, and the negative aspects from diffraction are clearly visible at 100% view as compared to f11; f22 would be significantly worse. However that said, IMHO a print made from that f16 capture would pass most close scrutiny, and the slight amount of added DoF is probably more beneficial than the slight loss of fine detail. However, f22 would probably go the other way...
    This is exactly why I'm beginning to think that it's one of the reasons many landscape photographers still use 8x10 - the larger surface of the 'sensor' is more forgiving to bigger diffraction, something that DMF cannot physically deal with, in fact it only gets worse as the Mega pixels are getting higher.

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jim2 View Post
    This is exactly why I'm beginning to think that it's one of the reasons many landscape photographers still use 8x10 - the larger surface of the 'sensor' is more forgiving to bigger diffraction, something that DMF cannot physically deal with, in fact it only gets worse as the Mega pixels are getting higher.

    That said, I'll bet there's a lot of wonderful 8x10 film images shot with 8x10 lenses that, printed at large size, don't look any sharper than an 80MP file shot at f22 with any optimal modern lens printed at the same size.


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  27. #27
    svema
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Hello Jim. Your question very difficult. Probably you are familiar with it: http:// http://www.luminous-landscape.com/tu...solution.shtml
    But it is not forgotten that the photo is light and a shade. And so in a shade just all the worst also is shown.
    Knowing I all it was afraid to change the Р45 + on Р65 + and has bought it only because it is the maximum size of a sensor control. My experience on Р65 + it F11. I remove a landscape and have come to Sinar р3. But it is my choice.

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Two points -- first, I have an Aptus-II 12 and wouldn't mind shooting a barrage of apertures and lenses to give you an accurate sense of how the decreased pixel element size affects diffraction.

    Second, why has no one mentioned hyperfocal distance? It seems the case that he's intending to shoot landscape images -- likely with a very wide-angle lens. I presume a 28mm, or something along those lines. If I focus my 28mm hyperfocally and shoot at f/16-f/18, the whole scene is reasonably sharp, maintaining excellent DoF. Certainly, if he's shooting a longer focal length, and attempting to maintain corner-to-corner DoF, there's going to be an issue, but with a shorter focal length lens, assuming he knows where to focus, this seems possible without resulting to f/22.

    From my experience, as well, f/22 on a P65+, which was my previous back, wasn't horrible, but it was notably less-sharp than f/16-18. I've yet to attempt it with my Leaf, but I'll try to post some samples tomorrow. Any requests on the focal length?

    Also, with the higher resolution, as diffraction becomes more of an issue, the effective resolution starts to ebb away. How much data you're actually recording at f/22 might not be any more than a P65+ at f/16. I've not done the math, but it seems like a worthy consideration to undertake. If you plan to consistently shoot at smaller apertures, it might benefit you to stick with a sensor that won't show the limitations of the optics as readily.
    Last edited by coulombic; 13th April 2011 at 13:04. Reason: Additional information to add.

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Disclaimer: The following is a purely theoretical statement and is no use if it doesn't hold up in practice.

    []Diffraction destroys some information (the convolution kernel is, unfortunately, zero in places), but much less than sampling does. A well enough sampled image that has been blurred by diffraction could in theory be well reconstructed through deconvolution sharpening. This may totally fail in practice and give ugly images.. I don't know. I have yet to take a photo where diffraction was the dominant source of lack of sharpness But it is a fairly regular and uniform source of image blur, and so should be tractable. [/]

    Matt

  30. #30
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by coulombic View Post
    Two points -- first, I have an Aptus-II 12 and wouldn't mind shooting a barrage of apertures and lenses to give you an accurate sense of how the decreased pixel element size affects diffraction.

    Thanks for the offer to take some examples with Aptus II 12. Mal's examples above seem like a good format for comparison - F11 vs F16 vs F22.
    On 35mm (Canon) Focal Lengths that I use vary from 35mm, 70, 105, or longer.

    Quote Originally Posted by coulombic View Post
    Also, with the higher resolution, as diffraction becomes more of an issue, the effective resolution starts to ebb away. How much data you're actually recording at f/22 might not be any more than a P65+ at f/16. I've not done the math, but it seems like a worthy consideration to undertake. If you plan to consistently shoot at smaller apertures, it might benefit you to stick with a sensor that won't show the limitations of the optics as readily.
    My question would be: A scene with the same framing/composition and the same F stop (in this case F/22), would it be better taken by an 80 MP back or a 60MP back, considering that the diffraction is affecting the 80MP back more adversely due to its smaller pixel size.

  31. #31
    Senior Member malmac's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Mal, I'm not sure if this is something you want to do (for fun!)

    - Capture tethered (to save time)
    - Set to AF at the barn area that we are looking at 100% crop
    - Take a shot - check shot result
    - Then switch lens to manual focus and adjust focus forward, take a shot, adjust focus back, take another shot

    See whether the AF is really doing its job properly?
    Jim2

    Though your suggestion was reasonable. Loaded software onto laptop, then realised I don't have a firewire port on laptop. Not able to shoot tethered at present. Damn.

    Decided I would try and reshoot the shed with a number of focus settings to see if I could get a sharper result more through luck and trial and error. So here is my very unscientific test results.

    My conclusion -
    Inconclusive result. No direct coparison with another camera so hard to say what is possible.
    The portion of the image being reviewed is realtively small when one zooms in. I guess if you zoom in far enough any digital image will get soft. I expected that the image would start to sharpen or blur more as I changed the manual focus, perhaps I may not have gone far enough to get to the sweetest focus point.

    Any comments welcome.


    Thanks Mal



  32. #32
    Jim2
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Mal,

    Thanks for doing this. I cannot see an 'obvious' difference. Nothing so striking. I was just thinking, as you said that maybe due to distance from the camera that's the best we can get? Perhaps try moving closer say to within 10m of the barn and see if we can get more sharpness. I noticed the artefacting of the jpg too. Maybe it's the lens that's not sharp..... The classic shots people make seem to be of a brick wall - see http://www.luminous-landscape.com/re...hoot_out.shtml

  33. #33
    SCHWARZZEIT
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jim2 View Post
    This is exactly why I'm beginning to think that it's one of the reasons many landscape photographers still use 8x10 - the larger surface of the 'sensor' is more forgiving to bigger diffraction, something that DMF cannot physically deal with, in fact it only gets worse as the Mega pixels are getting higher.
    Not necessarily, if you stop down to f/22 on 645 to get enough DOF you would have to use f/90 on an 8x10" to get similar DOF. The level of detail in one-shot photography can be ultimately limited by your DOF requirements due to diffraction.

    -Dominique

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Test I did with p40+, after upgrading from p30
    http://forum.getdpi.com/forum/showthread.php?t=18137

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by SCHWARZZEIT View Post
    Not necessarily, if you stop down to f/22 on 645 to get enough DOF you would have to use f/90 on an 8x10" to get similar DOF. The level of detail in one-shot photography can be ultimately limited by your DOF requirements due to diffraction.

    -Dominique
    Can you throw some math at me on how you got these numbers?

    If we're talking hyperfocal distance using "normal" lenses (80mm on 645 and 300mm on 8x10) with a subject distance of around 45m (based off of the picture in this thread) I imagine the required f-stop on 8x10 to match the "acceptable close focus" figure on f/22 with full-frame 645 is probably between 32 & 45--nowhere near f/90. (This is assuming we also want infinity in focus.) This is based off of experience shooting both medium format and 8x10. If I get the time I'll pull up the hyperfocal equations as I'm now intrigued.

  36. #36
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Quote Originally Posted by Jeremy View Post
    Can you throw some math at me on how you got these numbers?

    If we're talking hyperfocal distance using "normal" lenses (80mm on 645 and 300mm on 8x10) with a subject distance of around 45m (based off of the picture in this thread) I imagine the required f-stop on 8x10 to match the "acceptable close focus" figure on f/22 with full-frame 645 is probably between 32 & 45--nowhere near f/90. (This is assuming we also want infinity in focus.) This is based off of experience shooting both medium format and 8x10. If I get the time I'll pull up the hyperfocal equations as I'm now intrigued.
    With a subject distance of 45m you wouldn't use f/22 on 645 for DOF reasons with a normal lens. With a view camera you would tilt to increase DOF so there is no reason to go to f/90 unless you're in confined space.

    The math I used was simply that the 8x10" image format is about 4.5 times wider than 645 in each dimension. Thus the equivalent aperture for similar DOF is 4.5 times smaller. This calculation also covers the linear scaling of the COC.

    -Dominique

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    If you do the math, the smaller formats will gain DoF faster than they loose to diffraction at aperture X -- meaning they are more efficient. However, they also need to be enlarged more, so in reality it's becomes a sort of trading of deficits -- and it's been long accepted that MF through 4x5 is the sweet-spot happy medium.

    8x10 is preferred for movements over 4x5 because you can more easily see the effects of focus, tilts and swings on the GG than with 4x5. MF is preferred at the other end over 4x5, because they need less or no movements to carry DoF acceptably, where 4x5 does -- and you're focusing though a magnified finder, or with some focus confirmation electronics on board. (But if you do need tilts on MF, it is a real PITA to see them clearly on a ground-glass. Hence the huge benefit the IQ series Phase backs will offer to tech camera users with it's usable 100% frame view.)
    Jack
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Mal,

    I think your tests would be more effective if you would show the same section of the wall for each f/stop, not the pie chart thing you are doing. No 1 to 1 correlation of detail between the sections.
    wayne
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    Senior Member malmac's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    Wayne


    Thanks for the feedback.

    I sent one of the images to my camera lab and had them print out some 12x8 inch sections from the centre and the side of image from the f8 setting.
    The results are pleasing but still have some testing to do with the 65+ on the Cambo Wide DS with a 35mm Schneider lens to see how that works. Still dont have a laptop or a viewfinder so focus will come down to measuring the distance to the subjet.

    Thanks again for your help. A lot to learn but that is all good stuff.



    Mal

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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    All this math and physics and science is hurting my brain.
    I think I'll take my ALPA STC , 35mm SKXL, 80 MP Aptus and go out in the real world and take some beautiful pictures at whatever aperture I darn well feel like.....
    Cheers,
    Siebel
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  41. #41
    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Does anyone have (or know where to see) samples of IQ180 at F/22?

    As long as it is F11 go have a blast. LOL
    Photography is all about experimentation and without it you will never learn art.

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