J
Jim2
Guest
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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dougpeterson
Workshop Member
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/
Doug Peterson (e-mail Me)
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Guy Mancuso
Administrator, Instructor
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.
Guy Mancuso
Administrator, Instructor
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
J
Jim2
Guest
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)?
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)?
malmac
Member
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
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
GrahamWelland
Subscriber & Workshop Member
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.
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.
J
Jim2
Guest
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 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
J
Jim2
Guest
Is the DoF at F/11 that unforgiving (aka shallow)?
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
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
Bill Caulfeild-Browne
Well-known member
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
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
Wayne Fox
Workshop Member
Seems the link Doug posted had good examples of what you are asking. the difference between f/16 and f/22 was pretty pronounced.Sorry with all the questions
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.
dougpeterson
Workshop Member
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.
Doug Peterson (e-mail Me)
__________________
Head of Technical Services, Capture Integration
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Jan Brittenson
Senior Subscriber Member
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.
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.
malmac
Member
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
J
Jim2
Guest
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!
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!
J
Jim2
Guest
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?
- 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?
Guy Mancuso
Administrator, Instructor
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