AF fine tune - LensAlign, DotTune, or other methods?

roombarobot

To help get the sharpest images, I'd like to fine tune my D800E for my lenses. I've tried just using a ruler on a table and found that to be a bit challenging. I see that there are tools like the LensAlign system, but they look quite overpriced.

I found this method and associated tool on dpreview:
http://forums.dpreview.com/forums/post/50080741

And several folks were talking about DotTune:


Does anyone have experience with any of these options or advice about other methods to fine tune the autofocus?

JJ_SO

Hmm, I didn't need more than five minutes with the ruler, I think. The ruler is KISS but I understand, we're conditioned to believe a soft- or hardware more than our own eyes Also, it's easier to adjust a fast lens because of shallo DOF.

More often I'm the problem, not the AF. :-??

DenverShooter

I use both LensAlign and FoCal. FoCal is nice because it interfaces to the camera and generates a graph. It takes effort to properly setup. LensAlign is inexpensive and easy to setup but it takes longer to use and it relies on your judgment.

Denver Shooter

DJBee49

I have used Focus Tune which is not expensive and seemed to work well. On re-testing the same lenses, it produced consistent results. It takes a little while to set up but is easy to use.

BabaGanoush

I found this method and associated tool on dpreview:
http://forums.dpreview.com/forums/post/50080741

Wrong link. I believe this is the correct forum discussion (it's a long thread BTW):

http://forums.dpreview.com/forums/post/50774257

roombarobot

No, I meant that link. I am putting three options out there, the LensAlign, the Fayard/dpreview jig for focusing, and the DotTune method. I wanted to start a discussion of the pros/cons/advice on any.

Thanks!

Msmoto

I suppose I am confused as to why the "Dot Tune" method says a five minute process, yet the video is almost 19 minutes long. Once the camera/target is set up, using a series of different AF Fine Tune settings and exposing on a Lens ALign Mk II, which is what I have, the process takes about 15 minutes. Using something like the Lens Align is IMO important as the alignment holes make certain the axis of the lens is perfectly at right angles to the target. Without perfect alignment, the process has errors.

Possibly a utilization of both the "dot" method and the AF Fine Tune adjustments with images on a Lens Align, would obtain the best results.

Correlli

I had Nikon do this for me (within the warranty period). I also played around with rulers and some focusing targets.

I did have a look at the FoCal Software (or to be more precise: I looked at their videos). What I found interesting is the option to do more than one shot a a given setting. I would really be interested in doing a series of images at the same AF tuning setting (or without fine tuning) to see what the variance at a given distance is. Something like: put the camera on a tripod and have the AF focus on a target. Take the image and calculate the sharpness value. Manually de-focus the lens and repeat (use AF, take image and get sharpness value).

Has anyone done that?

horshack

I suppose I am confused as to why the "Dot Tune" method says a five minute process, yet the video is almost 19 minutes long. Once the camera/target is set up, using a series of different AF Fine Tune settings and exposing on a Lens ALign Mk II, which is what I have, the process takes about 15 minutes. Using something like the Lens Align is IMO important as the alignment holes make certain the axis of the lens is perfectly at right angles to the target. Without perfect alignment, the process has errors.

Possibly a utilization of both the "dot" method and the AF Fine Tune adjustments with images on a Lens Align, would obtain the best results.

Hi, this is Horshack, the guy who did the DotTune video. The video is 18 minutes because it describes all the ins and outs of the method in detail. The sample DotTune session at the end of the video is 3 minutes, which includes extra time I spent to demonstrate what the VF feedback looks like beyond the normal tuning range. I can typically perform a DotTune in 90 seconds or less.

Msmoto

@ horshack

Thank you, and welcome to NRF. I will give this a try, and see how it goes compared to the Fine Tune target I use now. As I remember you have been in photography for awhile, yes?

Or, at least you have been on DPReview for a long time....

adamz

personally I'm using FoCal and it takes from 2 to 5 minutes to calibrate a lens. I went that way, as I believe that algorithm based calculations will give more accurate results than using my eyes.

scoobysmak

I am kinda glad to see this thread, I have been looking at lens calibration off and on. I really liked the first version of the lens align, the second one is way more portable it seems though, but usually I would calibrate my gear before I left home so to travel with it would be just something else to weigh me down.

I calibrated my monitor and printer so time to do the camera, I do like the pro version of FoCal that allows you to have more than one focus point, it doesn't calibrate more than one focus point at the same time, but this would give an overall idea of when and when not to use certian lenses or focus points. I do agree most of these seem expensive for what you get but if you have more than a couple of lenses and want the sharpest picture with the gear you own, overall its rather cheap.

adamz

I would say, if You spend $$$$ on camera and lenses than is the additional $$ really such a big investment in order to get the most from Your system? after all, that's one of the few factors of good picture: sharpness.

spraynpray

@Adamz: Pretty soon though all those $$ add up to $$$$$$ - shouldn't we expect cameras and lenses from the same manufacturer to work correctly?

adamz

@spraynpray - I totally agree with You that we should expect cameras and lenses from same manufacturer to work correctly, but reality differs a lot from expectations. and if I can choose to have a new bag or perfectly aligned lens to body than I prefer the second one. AF tune doesn't matter as much with cheaper lenses - if You have a lens that's 5.6 the DOF is much greater than on 2.8, especially on DX cams.

JJ_SO

I'd go for the new bag AND perfect adjusted lenses . I couldn't carry all of them with only two hands...

I agree, with lenses faster than f/2.8 it would be a shame to see their sharpness - but just not where it was supposed to be. Since I finetuned the cams and lenses, it happens more often that sharpness is where I needed it.

But not always.

And even when doing AF tuning, it happens a lot that AF got a clear target and missed it anyway. So this finetuning for me was kind of learning that AF is nothing totally 100% reliable - contrast AF gets more hits.

I did that last night and was amazed how some cameras/lens combinations are very reliable, others get like 60% bullseyes. Okay, with a DOF of maybe 1 inch or less I should expect some kind of tolerance in AF, too. Fast and very exactly usually excludes each other. It's like throwing a ballpen into a bottle while running.

And as for what to expect from manufacturers: I do expect they use tight tolerances, at least for the expensive cameras. But as a lot of parts and assemblies are included and simple use change the behavior and the (mechanical) colaboration between them, it's a good thing to check the AF accuracy from time to time and before critical shootings as well.

Msmoto

The most important lenses to calibrate, IMO, are the long ones. At 200 feet, the DOF on 800mm at f/8-11 is only a few feet if you like sharp images. Getting this where one wants it...AF will move this a foot or two at this distance, then one can really get nice stuff.

My guess is that no matter how good the equipment, there will always be some variation simply due to the fact we have mechanical connections which can only be so tight. There is also a finite amount of focusing the electronics can do. This accounts for why the "dot" method might work as one is looking at the limits of the system and finding a nice point in between.

NSXTypeR

Not really a question about how to calibrate the lens, more of a question about whether AF fine tune is calibrated to the focal length.

Say you have a 70-200 and you AF fine tune it at 70mm. Would it be possible that it throws off the AF at 200mm?

Just some random thing that popped into my head.

PB_PM

Yes it is possible, and it is often suggested that you fine tune zoom lenses towards the middle of the zoom range, or which ever end you use the most.

deejaysoul

I use Reikan FoCal, I emailed them a similar question and they recommended setting the AF Fine tune for the zoom end, since focus is most critical there.

haroldp

Canon supports separate fine tune adjustments at long and short FL's for zooms. We should encourage Nikon to do likewise.

I have also noticed focus shift at different f-stops even on primes, and usually fine tune for1 stop down from wide open.

.... H

Beso

This is one of the best articles I have read on lens calibration. It is not overly focused on all the technical issues in boringly dry detail but distills the complicated aspects affecting focus into easily readable and understandable prose. I highly recommend it.
https://photographylife.com/how-to-calibrate-lenses

Note: I currently use the Spyder LENSCAL focus tool but am looking into the FoCal system as a more comprehensive solution. And I caution about relying on the "green dot" to verify focus. I have a number of manual focus lenses and the focus ring can be rotated a fair amount while still maintaining the green dot in the view finder. Actual images bear out the fact that the focus may not be the sharpest while still shooting within the green dot range.

heartyfisher

Offtopic : but bring on mirrorless .. once the mirror is gone we wont have this issue anymore.. calibration can be done automatically .. Hmm .. come to think of it. it probably can be done now in a calibration mode.

Killerbob

PB, I agree with you, and did that for the longest time. Then one day I tried out one of the recommended methods, and wow, it was much better than I ever could adjust it too just by winging it. I then invested in the Raikan Focal system (shared the cost with a friend - you can register 5 cameras), and that was a real eye opener.

However, if you really want it adjusted properly, get your moneys worth, and have a Nikon service Center do it right. Here in Denmark it is a free service with any pro camera and lens combination. That way you get it fine tuned for your combination, and they actually AF fine tune the zooms for several settings. My 80-400mm I believe have 6 points. No way you can adjust for that in any way manually.

PB_PM

That's not a greatest method, because the computer screen is a semi-flat object, while most objects that would be targeted in real life are 3D. But hey, if it works, why not?

Frankly I've never found AF fine tuning overly helpful, because the setups often direct the user to be much too close to the subject matter. I guess they are fine if you focus on subjects that are 1-2 meters away, but that's rare in real life, for me anyway.

spraynpray

+1 PB_PM although I haven't ever noticed any focus problems on PitchBlack's images.