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Thread: Stop down focusing - Advice

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    Stop down focusing - Advice

    Hi!

    With my manual lens wide open I can use peaking (somewhat accurate @f1.4) and zoom in view (very accurate but slow) to achieve good focus with my A7r.

    When however I'm at f4 and certainly by f8, it's all out of the window. Peaking is no longer accurate at all and zoom in focusing is every difficult as it's hard to find the actual plane of focus.

    Now the most sensible way to combat this is to focus wide open and then stop down. This however is not possible with a model in the studio and to be frank a pain in the neck even when you have the time or a tripod (each lens having a different number of clicks from wide open to your f-stop depending on starting point).

    I've always worked with focusing systems which were focused either wide open or non TTL. Bit lost as to how to best work with stopped down accurate focusing. A recent session with a model in the classroom left me with a 35% OOF ratio shooting at f4-5.6, in every shot I had strong peaking in the catch lights of the eyes. Unacceptable ratio of course when you need results. Unfortunately when shooting studio you need to turn 'Effect Settings' off and you can't set the viewfinder for B&W or max contrast to help see the peaking better.

    Your advice much appreciated!

    (image focus ended up at the back eye, front eye is soft. 50mm @ 5.6)


    Nailed it with this one, no 50+ year old lens has a right to be this sharp on a teenagers face!

    Last edited by Ben Rubinstein; 18th January 2014 at 13:34.
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    Re: Stop down focusing - Advice

    Nice shots Ben!

    Why not use f/8+? In the studio for shots like these, narrower DOF isn't the objective … just crank up the lights a stop or so.

    Other wise, all I can say is … practice using the 1st step magnifier. It's a new way of shooting, but you get used to it.

    - Marc

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    Re: Stop down focusing - Advice

    This was just a basic lighting class showing a single light in the first and separation light added in the second and using students as sacrificial models How do you use magnifier with people though Marc? It's a slow way of working I find. Thing is that at f8 it gets even harder to nail focus when the peaking it showing everything in focus everywhere.
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    Re: Stop down focusing - Advice

    I've been using adapted, stopped down manual lenses on TTL viewing cameras for some time (since 2008, with the Panasonic G1).

    I think the only real answer is lots of practice. I usually use focus peaking (when available) to rough in the focus quickly and magnification to obtain critical accuracy. Current EVF technology is generally speaking very very good, with the E-M1 I don't find I need to magnify or use peaking a good bit of the time.

    The A7 body is here but I haven't got a lens adapter for it yet, so I can't say anything about the quality of its EVF so far.

    G

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    Re: Stop down focusing - Advice

    It didn't help that the black backdrop confused the EVF and made it overexpose I suppose.
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    Re: Stop down focusing - Advice

    I now have a Summicron 75 with my A7R. Ti slens is sharp wid eopen, which means when DOF is really narrow. I find that focusing wide open and then stopping down yields better results even when I shoot at f:5.6. Just my 0.02$

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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    It didn't help that the black backdrop confused the EVF and made it overexpose I suppose.
    Huh? I don't understand this.

    In studio using strobes, did you set the Live View Display to "Setting Effect Off" ? … otherwise, the viewfinder is to dark at f/5.6 or 8.

    Anyway, I don't rely on peaking as much as the mag in darker conditions, and frankly it just takes practice just like anything else. Look through the viewfinder and adjust focus per the peaking and then hit the mag button … half the time what you thought was in critical focus, isn't.

    Try turning off peaking and practice using the mag technique for studio work … it gets rid of all the distracting jumping around peaking stuff at 7X mag. (14X is to grainy to judge in a dark room IMO).

    The only thing both Guy and I found was that the shutter button is to sensitive … so when you hit the mag button to critically focus, if you even breath on the shutter button it jumps back out to full view.

    I'm getting it down pretty well now, even shot kids doing the limbo in a super dark room with the Noctilux set at f/0.95 to f/4 … I magnified the limbo bar, and when the kid was just going under took the shot. Studio work is a LOT easier than that.

    - Marc

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    Re: Stop down focusing - Advice

    Heresy: get a 55mm f1.8 and use face detect and eye detect.

    The shame....
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    Re: Stop down focusing - Advice

    I have very similar issues with the A7r in brighter ambient lighting with the 50 Cron Rigid DR, and 24 Lux at f/4 to f/8 for seascapes. As Marc has suggested I have set, "Settings to off", but for visually seeing accurately I turn on the LV to "Bright Sunlight", and EVF to manual and set the brightness to max of +2. This does help a lot, in being able to see detail to accurately focus. Focus peaking with practice is similar to using the RF with the M9/M240. Some practice is needed, but now I rarely need to use the mag view, even with the 50 Noct f/1.0 wide open. Moving it slightly back and forth, will give the range, and knowing the lens it will get easier, and only when the focus peaking is not clear, I then use the mag view.

    Regarding the dark EVF with MF lenses, I had reported this issue already with Sony Australia, as had a number of other people. Whether in Australia, we have many instances with brighter ambient lighting, and for landscapes and seascapes f/5.6 and 8 are the norm, so this is an issue, hopefully that can be addressed.

    Since using the FE 35 and 55, there are no issues with the dark EVF with the same lighting that was causing the very dark EVF at f/4+.

    My work around for now is to just increase the brightness of both the EVF and LV for stopped down MF lenses
    Charles Kalnins
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    Re: Stop down focusing - Advice

    Manual focussing wide open and then stopping down may not produce sharp images if the lens you are using has focus shift (most fast lens have it), no matter how accurate is your focussing technique.
    Ario
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    Re: Stop down focusing - Advice

    Quote Originally Posted by fotografz View Post
    Huh? I don't understand this.

    In studio using strobes, did you set the Live View Display to "Setting Effect Off" ? otherwise, the viewfinder is to dark at f/5.6 or 8.

    Anyway, I don't rely on peaking as much as the mag in darker conditions, and frankly it just takes practice just like anything else. Look through the viewfinder and adjust focus per the peaking and then hit the mag button half the time what you thought was in critical focus, isn't.

    Try turning off peaking and practice using the mag technique for studio work it gets rid of all the distracting jumping around peaking stuff at 7X mag. (14X is to grainy to judge in a dark room IMO).

    The only thing both Guy and I found was that the shutter button is to sensitive so when you hit the mag button to critically focus, if you even breath on the shutter button it jumps back out to full view.

    I'm getting it down pretty well now, even shot kids doing the limbo in a super dark room with the Noctilux set at f/0.95 to f/4 I magnified the limbo bar, and when the kid was just going under took the shot. Studio work is a LOT easier than that.

    - Marc
    Try it Marc. Set to 'settings effect off' and point at something black. Viewfinder 'autoexposes' the scene and as usual with overexposure, tries to make the scene mid grey.
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    Re: Stop down focusing - Advice

    Quote Originally Posted by tashley View Post
    Heresy: get a 55mm f1.8 and use face detect and eye detect.

    The shame....
    I really want to like that rendering but I can't. I've never like the zeiss look and I just don't think that the sonnar is a 'people' lens. Not unless you want them to hate you for ever.
    Last edited by Ben Rubinstein; 19th January 2014 at 00:30.
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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    Try it Marc. Set to 'settings effect off' and point at something black. Viewfinder 'autoexposes' the scene and as usual with overexposure, tries to make the scene mid grey.
    Hmm, something is amiss Ben.

    I'm in a dark studio room, one incandescent flood light at one corner of the room grabbed my A7R @ ISO/320 with a Leica M 35/1.4 set to f/8, menu to "Setting Effects Off", pointed it at my 6' X 6' black felt flag and it is totally black in the viewfinder and LCD.

    It does register the light in room beyond in the way an OVF would allowing for mag view focusing, but if you shoot it, it is grossly under-exposed as you'd expect @ ISO/320 and f/8 in a room this dark. Strobes would then light it correctly for actual exposure.

    So, I do not know what you are doing that causes the over-exposure of the black background in the viewfinder

    UNLESS you have the lens aperture set wide open "Setting Effects Off" is used at working aperture (not wide open). If I point at the same felt flag and open up the M35 to f/1.4 it over-exposes and the lit room beyond also overexposes but much less so because it isn't as dark a scene when averaged to middle grey but would be completely blown out if strobes were fired.

    If I switch to "Setting Effects On", ISO/320 at f/8, the entire EVF and LCD are all but blacked out just like the actual exposure would be. Totally useless when working with strobes in a dark room.

    "Effects Off" is done at working aperture so you can see to focus when using low ISOs and stopped down.

    I have to work the same way in studio with the Sony A99/SLT works like a charm in fact, the A99 and A7R are the easiest to focus cameras I've ever used in a dark studio environment.

    - Marc

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    Re: Stop down focusing - Advice

    I have viewfinder brightness set to auto. Is that it?
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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    I really want to like that rendering but I can't. I've never like the zeiss look and I just don't think that the sonnar is a 'people' lens. Not unless you want them to hate you for ever.
    Not a fan of 55mm for most "dedicated" people work from any maker what we need is a Zeiss Planar prime like the ZA 85/1.4 actually f/2 would be okay.

    Personally, I like the Zeiss look and feel this client didn't hate me forever

    - Marc

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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    I have viewfinder brightness set to auto. Is that it?
    Mine is set to Auto also.

    Is the lens set to working aperture?

    - Marc

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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ario Arioldi View Post
    Manual focussing wide open and then stopping down may not produce sharp images if the lens you are using has focus shift (most fast lens have it), no matter how accurate is your focussing technique.
    So right you are..... Focus wide open then stop down to f5.6 and what was in focus is now out! Very frustrating as most of the lenses I own have some focus shift. Focusing wide open is OK if you shoot wide open. Focusing at the working aperture can be difficult and can lead to some unusual results given field curvature. Practice.....practice.

    Victor

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    Re: Stop down focusing - Advice

    Then try focussing at f4 and then stopping down. I also tend to 'come at' magfoc from far, which helps.

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    Re: Stop down focusing - Advice

    Quote Originally Posted by vjbelle View Post
    So right you are..... Focus wide open then stop down to f5.6 and what was in focus is now out! Very frustrating as most of the lenses I own have some focus shift. Focusing wide open is OK if you shoot wide open. Focusing at the working aperture can be difficult and can lead to some unusual results given field curvature. Practice.....practice.

    Victor
    Read the OPs original post he is working in a studio with lighting which is usually a relatively dark environment.

    "Setting Effects Off" is the only way to work even with modeling lights.

    Working aperture is NOT difficult because you are NOT looking at the scene at that level of f/5.6 to f/8 darkness in the VF that is what "Setting Effects Off" means it is nicely bright so you can focus.

    Field curvature is a non-issue when using the mag for critical focus it only magnifies the section you want in critical focus. In this case, the subject's eyes.

    I do not know what is so difficult to understand about this?

    I've used the A99 for well over a year, and now the A7R in studio with zero issues.

    - Marc

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    Re: Stop down focusing - Advice

    My god..... simmer down... take a deep breath!! The world's not coming to an end.

    Victor

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    Re: Stop down focusing - Advice

    Hi Marc,

    The zeiss look fits very nicely with your style, you always make it sing. Not for me though.

    Can you explain what you mean by working aperture? I was shooting at f4-5.6 and focusing using that aperture on a manual lens. i.e. stopped down physically.
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    Re: Stop down focusing - Advice

    I think what Victor is referring to is that if you focus wide open then close down then you could well have focus shift (50mm lenses are notorious for it) so that even were you to choose that option, you would not get any more accurate focusing. In that you are on the same page.
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    Re: Stop down focusing - Advice

    Just another pic, one of my first with my Pentax M/85 f2 shot wide open. Small lens. Really hard to focus with peaking, it shows peaking clearly enough but I need to magnify to get accuracy. My daughter offered to pose.

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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    I think what Victor is referring to is that if you focus wide open then close down then you could well have focus shift (50mm lenses are notorious for it) so that even were you to choose that option, you would not get any more accurate focusing. In that you are on the same page.
    Yes Ben..... that's exactly what I'm referring to. And you are right in that 50mm is very susceptible. My 50mm Zeiss Planar seems to be somewhat exempt but my 50mm Leica Summicron M is a big time shifter. Table top would/could be difficult with a lens that shifts and would take practice to know what to expect.

    Victor

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    Re: Stop down focusing - Advice

    Admittedly from my experience the DOF negates focus shift by f4 or so. Is that the case with your lens?
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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    Admittedly from my experience the DOF negates focus shift by f4 or so. Is that the case with your lens?
    I'm not exactly sure what you are saying..... but, as an example I like shooting my 50mm Leica at f5.6. If I focus at f2 and then shoot at f5.6 the focus point has now been moved behind the original focus point. If I focus at f5.6 and shoot at f5.6 the subject is in focus but field curvature has now destroyed the edges (if that was important). I used a lensalign to 'see' how much shifting was taking place at each aperture - very amazing how much shift takes place!! I found, by trial and error, that if I use f3.5, which is a little into the shifting, it seems to be a good compromise for getting most everything into focus at f5.6. I like using the fist level of magnification in the EVF as it also incorporates peaking which is useful but there are times when maximum magnification is necessary. It really requires a little time and practice. Ideally a lens that does not shift is the 'real' solution.

    Victor

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    Re: Stop down focusing - Advice

    Ben,

    If you mean 'does f4.0 bring the focus point back if the original focus was at f2.0' the answer is a definitive 'No'..... at least with my 50mm Summicron. That lens shifts so much that it would take f11, if that, to completely mitigate the focus shift.

    Victor

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    Re: Stop down focusing - Advice

    Really? With my 50L, a lens well known for its focus shift, by f5.6 the focus shift was negated by the additional DOF.
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    Re: Stop down focusing - Advice

    I wish my analysis wasn't the case but it is for my 50mm Leica. My Zeiss 50mm Planar is immune and will probably become my lens of choice. I love the size of the Leica but the shifting is very troublesome. There is only 'one' focus point and I would like to predict that point accurately.

    Victor

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    Re: Stop down focusing - Advice

    I am somewhat surprised that with your 50mm cron that the growing depth of field by 5.6 doesn't compensate for focus shift with that lens. Generally I've found with most lenses that exhibit focus shift, that by around f 5.6, most of the subject focused on is within a good portion of the zone of "what's in focus"". That's an amazing amount for focus shift. Interesting! That's an amazing degree of focus shift if you need to stop down to f 11 to compensate.

    Dave (D&A)

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    Re: Stop down focusing - Advice

    I agree with you, Dave. My 35 Lux ASPH has definite shift (pre FLE) and when using it on the M9 you can't adjust except by guesswork. So with the M9 I either shoot at F1.4 if DOF is not an issue or F5.6 where the DOF conceals the shift.

    The great thing about the a7r is that you CAN focus at the taking aperture, albeit carefully.
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    Re: Stop down focusing - Advice

    Exactly Bill! I know that lens well, one of my favorites even though it had the focus shift you described. Most are adjusted for best focus at f1.4 but I had mine optimized for f2 so that at f1.4 there was a smidgen of front focus at that aperture and a smigin of back focus at f2.8. By f4 the growing depth of field caught up with the focus shift and subject was in focus.

    Dave (D&A)
    Last edited by D&A; 19th January 2014 at 12:00.

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    Re: Stop down focusing - Advice

    Quote Originally Posted by Ben Rubinstein View Post
    Hi Marc,

    The zeiss look fits very nicely with your style, you always make it sing. Not for me though.

    Can you explain what you mean by working aperture? I was shooting at f4-5.6 and focusing using that aperture on a manual lens. i.e. stopped down physically.
    Yes, you are right Ben per your original question with accompaning images i.e., in studio portraits with lighting.

    You simply set the lens aperture at f/5.6 or f/8 or whatever you need for the strobe lighting exposure, and mag focus at that "working aperture". There is no need to open up the aperture, focus, then stop down but only IF you have the "Live View Display" menu item set to "Setting Effect Off".

    So, there is no focus shift because you are already stopped down when focusing.

    - Marc

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    Re: Stop down focusing - Advice

    Quote Originally Posted by D&A View Post
    I am somewhat surprised that with your 50mm cron that the growing depth of field by 5.6 doesn't compensate for focus shift with that lens. Generally I've found with most lenses that exhibit focus shift, that by around f 5.6, most of the subject focused on is within a good portion of the zone of "what's in focus"". That's an amazing amount for focus shift. Interesting! That's an amazing degree of focus shift if you need to stop down to f 11 to compensate.

    Dave (D&A)
    Dave,

    I live on a 4 acre parcel with trees everywhere and this gives me lots of targets for checking this stuff out. In this case I focus on a large tree that is 75 feet away (measured by my Disto). Camera is on a tripod and level. If I focus at f2.0 and shoot at f5.6 the target is out of focus..... the focus point is behind the tree and can easily be verified by surrounding trees. If I focus at f3.5 and shoot at f5.6 I'm on the money. That's because I've focused a little ways into the shift..... enough to keep the DOF sufficient to be in focus at f5.6. I also think that the distance to the focus target has some effect with closer targets being more forgiving although I have not done a lot of testing for this. I could post images if you would like..... however there's no way to verify anything because there is no exif data.

    Victor

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    Re: Stop down focusing - Advice

    Quote Originally Posted by vjbelle View Post
    Dave,

    I live on a 4 acre parcel with trees everywhere and this gives me lots of targets for checking this stuff out. In this case I focus on a large tree that is 75 feet away (measured by my Disto). Camera is on a tripod and level. If I focus at f2.0 and shoot at f5.6 the target is out of focus..... the focus point is behind the tree and can easily be verified by surrounding trees. If I focus at f3.5 and shoot at f5.6 I'm on the money. That's because I've focused a little ways into the shift..... enough to keep the DOF sufficient to be in focus at f5.6. I also think that the distance to the focus target has some effect with closer targets being more forgiving although I have not done a lot of testing for this. I could post images if you would like..... however there's no way to verify anything because there is no exif data.

    Victor
    That is quite weird, because usually the nearer your target is, the shallower the DOF. I would rather assume that with objects standing further away the DOF would be greater and thus focus errors more forgiving.

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    Re: Stop down focusing - Advice

    Not with wider angled lenses. Because, by neccessity the focus throw is less precise with a wider angle lens, a shift instead of being a small percentage, ends up being a large percentage. At least that is how I understand it. It's the reason why shimming of a wide angle lens is so much more crucial than a longer lens.
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    Re: Stop down focusing - Advice

    Quote Originally Posted by vjbelle View Post
    Dave,

    I live on a 4 acre parcel with trees everywhere and this gives me lots of targets for checking this stuff out. In this case I focus on a large tree that is 75 feet away (measured by my Disto). Camera is on a tripod and level. If I focus at f2.0 and shoot at f5.6 the target is out of focus..... the focus point is behind the tree and can easily be verified by surrounding trees. If I focus at f3.5 and shoot at f5.6 I'm on the money. That's because I've focused a little ways into the shift..... enough to keep the DOF sufficient to be in focus at f5.6. I also think that the distance to the focus target has some effect with closer targets being more forgiving although I have not done a lot of testing for this. I could post images if you would like..... however there's no way to verify anything because there is no exif data.

    Victor
    Victor, perhaps your lens is in need of calibration?

    Some years ago I had a technically minded friend bench test each of my M lenses with the intent of getting them as close to how I tend to shoot (average distance/and most common F/stop) and of 7 lenses, 5 needed to be calibrated by Leica. After that, even my M35/1.4 ASPH pre FLE is quite accurate and suffers less from focus shift than prior to re-calibration).

    As evidence of calibration needs, many DSLRs now have in-camera calibration for individual lenses which then can be saved (including non-native lenses without data bus contacts) and of the Canon, Nikon and Sony gear I've used, the amount of lenses in need of calibration was surprising. My first Sony ZA-24/2 was so off, I sent it back and the replacement only needed a -2 adjustment.

    There is a micro adjust feature in the A7/A7R menu, but the menu says AF Micro-Adjust which sounds like a global calibration rather than individual lenses like the A99 can do which is unfortunate since it'd be nice if you could do it with any manual focus lens.

    Anyway, your 50mm experiences, and other people questioning those experiences compared to their's, seem to indicate a need for calibration perhaps?.
    - Marc

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    Re: Stop down focusing - Advice

    Focus calibration is of course relevant however focus shift is a well documented phenomenon albeit far more relevant in the world of very high resolution sensors. The canon 50L is a famous culprit of this problem. However well you calibrate the lens, the calibration is wide open. When you close down the focus shifts. The CV 50mm 1.5 Sonnar is also well known for this causing its reputation in the film days for being 'dreamy'. The advantage of focusing at the shooting aperture, as you and Victor have pointed out, is that you no longer need to worry about this problem. Incidentally lenses with a floating element such as the 50mm 'lux asph do not have a focus shift issue. There is a lot of grumbling about canon being too cheap to put one in the 50L which is a very expensive lens.

    Focus calibration is only relevant to phase detect focus systems. Contrast detect focus systems such as the A7r do not have the problem of focus misadjustment. On the A7r it is included for use with the sony adaptor with the mirror (as I understand it) which does have phase detect AF. Whether individual lenses can be calibrated when using it is not something I know I'm afraid.

    Anyway back to work and trying to work out what to replace our Phase One DF camera with having blown through the second shutter in a year....
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    Re: Stop down focusing - Advice

    Interesting info Ben. The AF Micro Adjust is greyed out on the A7R with FE lens, but I have the LAEA-4 adapter for my ZA A mounts on the A7R, so will mount it and see if the AF Micro Adjust becomes available (?) It still sounds like it is a global adjustment rather than an individual lens calibration.

    RE: calibration I understand focus shift is well documented of interest is Hasselblad's approach to the issue. The original "True Focus" feature wasn't off-center focusing and adjustments to correct for re-framing that was added later as TF-APL (Absolute Position Lock).

    The original TF was to automatically micro adjust every HC/HCD lens for focus shift at any aperture used. It was all programmed into the camera's data bank.

    So it can be done.

    - Marc

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    Re: Stop down focusing - Advice

    Yeah the camera manufacturers are just lazy. A firmware update with a focus adjust table automatically implemented to adjust based on focus shift amounts at each aperture would have stopped certain lenses, especially the 50L, having gained the reputation of being 'great but'. A day's work for a technician to do the testing. Shame really.
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    Re: Stop down focusing - Advice

    Quote Originally Posted by Annna T View Post
    That is quite weird, because usually the nearer your target is, the shallower the DOF. I would rather assume that with objects standing further away the DOF would be greater and thus focus errors more forgiving.
    What you say is very true and certainly would apply if the focus was slightly off at the wide open aperture and there was 'NO' focus shift. The added DOF would probably completely mitigate the mis-focus. However with the shift I am experiencing the DOF is increased but shifted behind the lens and, of course, also in front - but not enough to make my target sharp.

    Victor

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    Re: Stop down focusing - Advice

    Quote Originally Posted by fotografz View Post
    Victor, perhaps your lens is in need of calibration?

    - Marc
    I don't claim to be a lens design expert but I don't know what calibration would cure. All I am doing is focusing and then ultimately stopping down. If calibration could cure shifting then I'm all in but I don't think there is a cure for shifting.

    If you have access to a LensAlign and a 50mm Cron take some images stopping down when focused at f2.0. My lens starts its gradual backfocus until f4.0 where it makes a big leap.... never saw anything like that before. Anyway I have my workaround.... focus at f3.5 - stop down to whatever and all is fine.

    Victor

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    Re: Stop down focusing - Advice

    Victor, by focusing at f3.5 and then stopping down, do fortunately works for a camera where you can implement live view when focusing. Unfortunately when using a camera like the Leica M9 and others without the benefit of live view, there is no way to circumvent focus shift unless one purposely misfo vises in front of the subject to compensate.

    I'm surprised to hear that your cron has so much focus shift. I was under the impression that most 50mm crons exhibit little if any. I assume your lend is spot on when shot wide open? Have you asked other users of the 50mm cron what their lenses are like with regards to focus shift?

    Dave (D&A)

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    Re: Stop down focusing - Advice

    Quote Originally Posted by vjbelle View Post
    I don't claim to be a lens design expert but I don't know what calibration would cure. All I am doing is focusing and then ultimately stopping down. If calibration could cure shifting then I'm all in but I don't think there is a cure for shifting.

    If you have access to a LensAlign and a 50mm Cron take some images stopping down when focused at f2.0. My lens starts its gradual backfocus until f4.0 where it makes a big leap.... never saw anything like that before. Anyway I have my workaround.... focus at f3.5 - stop down to whatever and all is fine.

    Victor
    Victor, you are entirely correct. Calibration applies only to Phase Detect Auto Focus and the only way to accurately focus a lens with shift is to use either live view or Contrast Detect, at the shooting aperture. I also totally believe you that your focus shift is as strong as you say: I don't have that lens, but I have had other Leica glass with quite serious shift. This can be compounded by the shape of the field of focus and the way it changes with subject distance and aperture.

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    Re: Stop down focusing - Advice

    since the M lenses are focused in the MM, Mx, only by the rangefinder method, how have people been dealing with the focus shift?

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    Re: Stop down focusing - Advice

    Quote Originally Posted by jlm View Post
    since the M lenses are focused in the MM, Mx, only by the rangefinder method, how have people been dealing with the focus shift?
    When shooting available light, the camera's Live View menu item is set to Setting Effect On what you see is what you get. So a properly exposed image is what you use to focus on no matter what aperture is selected. There is no shift, because you are focusing at working aperture.

    In a dark studio where strobes are providing the light only for a nano second, you may be stopped down so far with a higher shutter speed and a low ISO, that the ambient light in the studio is totally black in the viewfinder. Then you have to change the Live View menu item to "Setting Effect Off" so you can see to focus.

    - Marc

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    Re: Stop down focusing - Advice

    my question was more about the Leica MM, M9 environment, where presumably the same focus shift at differing apertures would occur, but there is no live view. i don't recall hearing so much about this except maybe with the noctilux

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    Re: Stop down focusing - Advice

    John, there was a lot of this stuff around when the M8 first appeared an people started to discover the pains of focus shift in a way that had been far less evident in the days of film. For example, Leica redesigned the 35 Lux because the pre-FLE version had such chronic focus shift. In general, for most affected lenses, people either switched or learned to live with it - which often meant testing their kit carefully to see what degree of shift happened at different subject distances and apertures and then tweaking their focus accordingly. But it was too hit and miss for me so I sold any lens I had whose shift outran its DOF as you stopped down.

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    Re: Stop down focusing - Advice

    That's what I found too - yesterday tested a Nikkor 105 AiS and found focus shift at around 3' on the A7 - using live view of course dealt the problems

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    Re: Stop down focusing - Advice

    John, refer to one of my previous posts above. With rangefinder cameras like the M9 or MM, you can sort of try compensating your focus (focus slightly in front of your subject) when shooting with a lens with known focus shift. This way when stopping down a bit, and the lens starts back focusing (focus shifting), your subject hopefully will be in focus. It's a crap shoot and sort of what Tim was suggesting.

    The other thing you can do is have the lens optimized for an f stop slightly stopped down rather than wide open. This will give a larger percentage of shots in focus when shooing between wide op en and f5.6. I describe the theory in one of my posts above.

    Dave (D&A)

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