Lens fine tuning.

[Mully]

This is what i use...

FocusTune

I watched the video on the site looks very interesting and affordable ....do you like this product?

I was a little skeptical at first.. but i'll admit... its addicting!

You can print out any target or use the one included (he has a new target in his forums). Then you take ~5 pictures at each focus adjustment in steps of 5.. (-20.. -15.. -10.. etc through +20). Load all ~45 images into the software and it will spit out a nice graph. Then you take the sharpest adjustment and do another set of images bracketing it by 5... for example, if it says -5 is your sharpest setting you'd take 5 images at each step -10 through 0. Run those images through the software and you'll have your sharpest adjustment setting.

Its SUPER easy.. and once you get rolling it only takes a few minutes to do.. It's also very consistent, every time I've tested a lens i get the same adjustment setting.

Best of all... its $30 and works on both Windows and OSX.

Very cool ...I am going to order it! Thanks much for the info

 

[Aloicious]

I tried the FoCal Software and wasn't very impressed with it. that focustune sounds interesting, but I just use something like what BCsteve has with a ruler, it's worked out much better, much faster, and the results are repeatable, unlike what I was getting from FoCal.

the camera will store a number of different combinations whit fine tune settings and auto-detect them (so like a lens, and lens + teleconverter can both be stored separately since it is different equipment, but otherwise its 1 AF setting per lens).

however, with a zoom lens you may have different calibration requirements at different zoom levels, so its best to do tests over a variety of zoom ranges, then choose the setting that is the best average correction value since only 1 setting can be input for the lens....so for example, if you're finding that at 24mm you need -6 and at 85mm you're needing -1....you can only put in one value for the lens, so you'd average them out and put in something like -3....or if you know you shoot at a specific zoom range the majority of the time, then you can target the settings for that range, like if you're getting the values in the example, and you know you're almost always shooting at 24-35mm, then you can set it to something like -4 or -5 to make it more biased towards that range.

if that makes sense...

also make sure you're placing your test target at a appropriate distance for the focal length you're testing, you don't want to be too close to the minimum focus distance, nor too far that you're at infinity either...I think most recommend 25-50x the focal length you're shooting at. though that number can vary, and you want to take into account how far you are from the subjects you normally are photographing too...

EDIT- also make sure when you're doing the test shots to use plenty of light so you can keep the shutter speed up, ISO low, and shoot with the lens wide open....also use mirror up mode and either a remote release or timer or something, with the tripod on a very stable surface (not on padded carpet or something like that), that way you eliminate as may variables as you can....and once you've input your calibrations, re-test it at the settings you've input to make sure you're getting repeatable and consistent results.

EDIT again - if you end up using something with a ruler like BCsteve or I do, make sure the ruler is metal and is straight, and is finely graduated (not just every 1/4 inch or something, you want good fine gradations so you can really examine and pick out the best settings, probably at least 1/32 inch, or full mm gradations on a metric scale) since the difference between 1 point and the next in the AF fine tune is very small you'll need to be able to SEE the difference between them.

 

[myko5]

Try this...

 

[Aloicious]

that green dot way is pretty good too, but IMO isn't quite as precise as closely examining the differences between the different settings, but it'll for sure still get you in a good area. You should get good results either way. I'd do either the ruler or green dot way LONG before I spend money on a software, considering how disappointed I was with FoCal...though I do know others who love the software, so, to each their own, but it just didn't do it for me.

In fact I'm going to fine tune my 600mm tonight (as well as a few others that I haven't been able to do yet), I brought it all with me to my second job at the hospital since this is the only place I know of that I have a LARGE empty interior hallway to use because w/ a TC, I'll need around 150 feet between the lens and the target to get in that 50x the focal length range. I'd have to be out on the sidewalk or road if I were to try it at my house, and being outside with wind, and vehicles driving by, and people around, too many added variables for me, my mind works too much like a scientist

 

[bc_steve]

...does the camera remember each different lens calibration?Or does one lens calibration cover all?

yes it remembers your calibration for each lens. You need to calibrate each lens separately. They will not all have the same adjustment.

the only problem as I said above is if you are using Tokina lenses. They used the same lens codes and the camera can't tell them apart in AF Fine Tune. Fortunately my 100mm macro is perfect at a setting of 0 so i can just turn of AF Fine Tune when I use that lens.

 

[Aloicious]

...does the camera remember each different lens calibration?Or does one lens calibration cover all?

yes it remembers your calibration for each lens. You need to calibrate each lens separately. They will not all have the same adjustment.

the only problem as I said above is if you are using Tokina lenses. They used the same lens codes and the camera can't tell them apart in AF Fine Tune. Fortunately my 100mm macro is perfect at a setting of 0 so i can just turn of AF Fine Tune when I use that lens.

I didn't know that about Tokina, is it only Tokina that you've found or do any other 3rd party lenses also have the same problem?

 

[bc_steve]

my only 3rd party lenses are the two Tokina's. I don't think it happens with any of the other 3rd party lenses but I am not sure.

 

[Aloicious]

well I have my 150mm Sigma macro w/ me tonight, that is another one I was going to work on tonight (though I don't think it needs any adjustment, it seems pretty dead on at zero), I'll see if it gives me any issues