Lens testing Equipment

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PAUL50

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Steve, in one of your videos you spoke of a particular piece of lens testing gear that you use for determining and fixing back or front focusing on a lens. It seems like I could use the product. It had a target and also a rail to determine where the lens was actually focusing. I think it might help me stop blaming the equipment for my soft shots. Currently I just use a flat target on a wall. Could you either refer me to the video or perhaps discuss it a little more here. I’m guessing that each lens would have a different correction for each camera it’s used on. Where can it be purchased and is it difficult to use? And finally, do you recommend it or is field testing enough. Thanks.
 
I use Lens align: http://michaeltapesdesign.com/lensalign.html You can purchase at B&H etc. I use their target but have modified their procedure and no longer use their software for analysis. You could do a decent test using the dot tune method, Google that for details. I've done field tests using fences, etc. I have found that temperature has an effect so what works in summer heat often needs to be adjusted in the cold of winter. I've gotten less picky as time goes on, if I'm in the ballpark it's close enough. All AF systems have variations, ie, af'ing on the same target multiple times will not give the same result every time, it varies a little one way or another.
 
I'll second the recommendation for a LensAlign kit as linked above. It's a bit pricier than some knock offs but is very good and their clever method to make sure you've aligned the camera and target to be square with one another is worth the higher price.
 
Information I posted in another topic about the Dot Tune method you might find helpful.
 
Information I posted in another topic about the Dot Tune method you might find helpful.
Thank you
 
@Warren D, @DRwyoming is the software worth getting? Or is the LensAligh sufficient? I haven't ended up buying one of these because the cheapos on Amazon have some negative reviews.
I don't use any software, just the target and then manual entries in the AF Fine Tune menus with test photos.

The cheap targets can work fine but the Lensalign is just a bit nicer. The key thing they add is a clever way to ensure that the camera sensor plane and target plane are truly parallel which is important for consistent results. They've patented that method so the cheaper knockoffs don't have that feature which means you have to be more careful during setup to make sure everything is set up perfectly square or the testing results can vary. FWIW, that's also why I don't try to do AF Fine Tune handheld, it's not a question of shutter speeds or motion blur, it's a question of keeping everything perpendicular and squared up throughout the testing.
 
I don't use the software anymore, it works, it just takes over 100 shots to get enough data to crunch. Multiply by numerous lens/tc combos and you can eat up 1000 or more clicks. Having done it often enough I can usually get my af fine tune nailed in less that 20 clicks per combo. As DR says the target is the best part. Just realize that every time you de-focus it will show slightly different focus points with every focus. It also is affected by the direction of de-focus. Also, I've found the more light on the target the more reliable the results.
 
I don't use any software, just the target and then manual entries in the AF Fine Tune menus with test photos.

The cheap targets can work fine but the Lensalign is just a bit nicer. The key thing they add is a clever way to ensure that the camera sensor plane and target plane are truly parallel which is important for consistent results. They've patented that method so the cheaper knockoffs don't have that feature which means you have to be more careful during setup to make sure everything is set up perfectly square or the testing results can vary. FWIW, that's also why I don't try to do AF Fine Tune handheld, it's not a question of shutter speeds or motion blur, it's a question of keeping everything perpendicular and squared up throughout the testing.
DR is there a formula or guideline that you use for distance to the target for a particular focal length? Thanks
 
I use Lens align: http://michaeltapesdesign.com/lensalign.html You can purchase at B&H etc. I use their target but have modified their procedure and no longer use their software for analysis. You could do a decent test using the dot tune method, Google that for details. I've done field tests using fences, etc. I have found that temperature has an effect so what works in summer heat often needs to be adjusted in the cold of winter. I've gotten less picky as time goes on, if I'm in the ballpark it's close enough. All AF systems have variations, ie, af'ing on the same target multiple times will not give the same result every time, it varies a little one way or another.
Question about those tools --
I don't use any software, just the target and then manual entries in the AF Fine Tune menus with test photos.

The cheap targets can work fine but the Lensalign is just a bit nicer. The key thing they add is a clever way to ensure that the camera sensor plane and target plane are truly parallel which is important for consistent results. They've patented that method so the cheaper knockoffs don't have that feature which means you have to be more careful during setup to make sure everything is set up perfectly square or the testing results can vary. FWIW, that's also why I don't try to do AF Fine Tune handheld, it's not a question of shutter speeds or motion blur, it's a question of keeping everything perpendicular and squared up throughout the testing.
Okay, so need to order that and get my 180-400 (1.4) calibrated!
Question: is the same calibration process that Nikon would do if I sent it in and had them do it?
Question 2: Am I calculating this correctly -- for the 560 mm end of the lens I'll need to have 90+ feet between camera and target?

Thanks!

ALSO at
 
DR is there a formula or guideline that you use for distance to the target for a particular focal length? Thanks
Question 2: Am I calculating this correctly -- for the 560 mm end of the lens I'll need to have 90+ feet between camera and target?
There are suggested distance calculators for AF Fine Tune such as this one: https://support.fo-cal.co.uk/article/27-af-calibration-target-distance-tool

That said, I do the AF Fine tune adjustments at the kind of typical distances where I'll use each lens and that tends to be closer to the close focus distance rather than a long ways away. I suppose if you'll regularly use a particular lens for subjects at a couple of hundred feet then you could fine tune at that distance but I'm much more concerned about how accurate the AF is at close distances where DoF is most limited so I just set up test targets out about as far as I'd normally focus for the lens in question or if in doubt, closer to the minimum focusing distance.
 
Recommend using a solid mount eg. a tripod and an off camera shutter release so you do not have to touch the setup too often (only to de-focus) during testing.
Good lighting of the target is also as @Warren D states, is also a must for me.
Good advice.

I'd also add that I intentionally manually de-focus the lens between each test shot to force the AF system to do its job each time and not give it a head start by leaving the lens pre-focused from the previous shot.
 
There are suggested distance calculators for AF Fine Tune such as this one: https://support.fo-cal.co.uk/article/27-af-calibration-target-distance-tool

That said, I do the AF Fine tune adjustments at the kind of typical distances where I'll use each lens and that tends to be closer to the close focus distance rather than a long ways away. I suppose if you'll regularly use a particular lens for subjects at a couple of hundred feet then you could fine tune at that distance but I'm much more concerned about how accurate the AF is at close distances where DoF is most limited so I just set up test targets out about as far as I'd normally focus for the lens in question or if in doubt, closer to the minimum focusing distance.
Ah, okay I get it now, so somewhere in those minimum and maximum distances Steve talks about. Thank you!
 
I have tried setting mine using a paper target but was never able to get it right. After looking at the link to lensalign I need to order one and try again.
I am asking for the wisdom of the experienced here about my D850 with Nikon 200-500 and D500 with same lens. How often are they actually correct without fine tuning? Because that is what I have been using. Sometimes I think it is off based on field results but sometimes not. 🤷‍♂️ Do you always have to adjust?
 
Do you always have to adjust?
No and I've even seen lenses that were helped with a small fine tune adjustment on a given camera body but then added a TC and in some cases needed no fine tune adjustment at all.

It varies from not needing any fine tune to sometimes needing a lot because it's the sum of any tolerancing errors for both the lens and the body in use and a TC if you add one. So for instance my 600mm f/4 showed a tiny bit of back focus on my D850, a tiny bit of front focus on my D500 and didn't need AF Fine tune adjustments at all on my D5 and that's just one lens on three different bodies.

Also as implied above, the further your typical subjects the more DoF you get for the same aperture so back and front focus tends to become a bigger issue as subjects get closer and DoF becomes much more limited thus not covering up tiny focusing errors. Similarly for the same focal length and subject distance you'll have less DoF based error margin on a wide open f/5.6 lens than a wide open f/4 lens so that plays into whether you 'need' to AF Fine Tune or not.
 
Also as implied above, the further your typical subjects the more DoF you get for the same aperture so back and front focus tends to become a bigger issue as subjects get closer and DoF becomes much more limited thus not covering up tiny focusing errors. Similarly for the same focal length and subject distance you'll have less DoF based error margin on a wide open f/5.6 lens than a wide open f/4 lens so that plays into whether you 'need' to AF Fine Tune or not.
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I see some testing in my future. Do you see any change say when there's a big temperature swing?
 
No and I've even seen lenses that were helped with a small fine tune adjustment on a given camera body but then added a TC and in some cases needed no fine tune adjustment at all.

It varies from not needing any fine tune to sometimes needing a lot because it's the sum of any tolerancing errors for both the lens and the body in use and a TC if you add one. So for instance my 600mm f/4 showed a tiny bit of back focus on my D850, a tiny bit of front focus on my D500 and didn't need AF Fine tune adjustments at all on my D5 and that's just one lens on three different bodies.

Also as implied above, the further your typical subjects the more DoF you get for the same aperture so back and front focus tends to become a bigger issue as subjects get closer and DoF becomes much more limited thus not covering up tiny focusing errors. Similarly for the same focal length and subject distance you'll have less DoF based error margin on a wide open f/5.6 lens than a wide open f/4 lens so that plays into whether you 'need' to AF Fine Tune or not.
Thank you for the quick reply. I have one more question. How often do they fall out of tune? Should a person be checking it periodically or just keep eye on results.
Thanks again, I can't tell you how much the advice on these forums means to dummies like me. (y)
 
Thank you for the quick reply. I have one more question. How often do they fall out of tune? Should a person be checking it periodically or just keep eye on results.
Thanks again, I can't tell you how much the advice on these forums means to dummies like me. (y)
Sorry, I don't have a good answer for that one.

I suspect it has to do with handling of both the camera and lens and things like any temperature extremes they've been subjected to. I che mine at least once a year and before big trips (at least my go to lens for that trip like my 600mm f/4) but I usually don't have to make changes or at least big changes.
 
Sorry, I don't have a good answer for that one.

I suspect it has to do with handling of both the camera and lens and things like any temperature extremes they've been subjected to. I che mine at least once a year and before big trips (at least my go to lens for that trip like my 600mm f/4) but I usually don't have to make changes or at least big changes.
Thanks again, probably a good idea to check it if preparing for something important.
 
Thank you for the quick reply. I have one more question. How often do they fall out of tune? Should a person be checking it periodically or just keep eye on results.
Thanks again, I can't tell you how much the advice on these forums means to dummies like me. (y)
As I said previously, i've seen changes in my 600 EFL due to large temperature changes. I do a quick check when the temps are in the 70's and again when they drop to mid 40's. Kinda like checking tire pressures when the seasons change. YMMV......
 
As I said previously, i've seen changes in my 600 EFL due to large temperature changes. I do a quick check when the temps are in the 70's and again when they drop to mid 40's. Kinda like checking tire pressures when the seasons change. YMMV......
Thanks, yeah it makes sense. Now I just need to finally get it right...
 
If you want to check if your camera / lens/es are not in focus then I suggest that you first try Dot Tune, if you have no success then buy something.
I cannot suggest any software that you may decide to buy, I do know Dot Tune worked for me.

You will need to check all combinations of cameras and lenses that you have as each combination may need individual settings, some may not.
When you are proficient with the Dot Tune process you can check the combinations quite quickly.

With the D500 there are 20 different settings to use for different combinations, that should be enough for most of us?
The D500 will list the lens and combinations of lenses for Nikon lenses but not sure about all other manufacturer products, Tamron 90mm macro is detected.

Sorry (EDIT), forgot to emntion the D500 changes the settings automatically for each lens/tc combination witn no user input needed.
 
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Another factor to consider. (I obtained this from a reliable source and have personally experienced the end result) A couple of years ago, I fell while carrying my D5 and 70-200 EFL. The camera/lens contacted a railroad rail (solid steel) and while it appeared there was only cosmetic damage, I suspected damage to the mount and possibly internals. I sent both to Nikon for repair. When the D5 came back, all my previous AF fine tune values (still saved) were off by 7 units. Well into calibration I noticed that each lens/tc combo seemed to need the same 7 unit adjustment to the previous setting.
I contacted Nikon as the repair had been outsourced and sent it in again. It returned with a note that all was set to factory specs. Now the D5 is (or was at the time) their flagship camera made in Japan so it should have been "to factory specs" when I bought it. After an e-mail reply from a well known Nikon expert, this is the answer:
Nikon's calibration equipment that they use in all repair facilities has a 7 unit bias. The factory calibration units are fine but the repair stations were out when they were built. I was told that Nikon has been made aware of this but due to the expense involved in re-building all the current calibrators world wide, they have chosen to address it in the future when the existing calibrators are replaced.
The point of this is that lenses and bodies serviced by any repair facility will have a 7 unit af fine tune bias over factory settings. If both the lens and body are serviced (or have been in the past) the bias cancels out but will still be there compared to un-serviced gear.
For just the body, the repair calibration adds 7 units of AF fine tune front focus. My experience is that most of my lenses have required 5-15 units of back focus on factory calibrated bodies, add 7 more to that for the repair calibration.
The point is, if you send your gear in for service, even though the af fine tune values are still in your menu, they should be checked and verified.
 
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