Sun 28-Apr-13 12:12 PM | edited Sun 28-Apr-13 12:15 PM by richardd300
Please bear with me as my experiences with both FocusTune used with LensAlign are very different from others and needs some explanation. Firstly, I had no reason to check my lenses as to me all was fine, I did the testing because others were and I don't like being left out and joking apart, I have a thirst for knowledge
I have no doubt whatsoever that these products are good at what they do, but didn't work for me sadly. Before I come onto the why's, let me talk about the setup procedures.
If you have the time and much patience the testing must be conducted in my view under almost laboratory conditions. As a previous poster has mentioned you are best using two tripods, one for the camera, one for the target. The height of the cameras focus point must be identical to the centre of the FocusTune target so the centre red dot is seen. Also, the camera and target must be level in both horizontal and pitch. For the Lighting I used a 300 watt halogen outside spotlight. Also, ensure a remote lead and Mup is used.
I did this for all my lenses, prime and zoom (more about zooms later). I should say at this point I have over 40 years experience in electronic instrumentation testing to a tolerance of +- 0.1%, so I know how important it is to have the right conditions. The results of the tests left me confused! In what ways:
I repeated tests under exactly the same conditions and received different results! Not tiny differences, but in some cases up to 5 or even 7 AF-Focus fine tune recommended variations. Now zooms and sorry to bore other readers as I always bang on about this. It is probably sensible to only check a zoom at it's most used focal length (effectively it's then a prime lens). I did to my 70-200mm f2.8 and FocusTune told me at 70mm it required a fine tune of +5, however at 200mm this was given as +20. There are those who recommend for a zoom one can set an average between the minimum and maximum focal length, I'm not sure that's satisfactory.
Since my earlier tests with my D800 I have recently repeated them with my D7100 and the results were as confusing as before. What worried me mostly was the lack of repeatability.
Finally, I have now abandoned all lens AF-Fine tuning. I will say however, there are dozens of folks on here and elsewhere who whole heatedly applaud both FocusTune and LensAlign. Therefore I must accept that perhaps I am doing something wrong.
Now, how do I test my lenses. If I have a concern and that is very rare and usually because my technique failed me a few times, I use a flat ISO approved target at set distances. I repeat the tests in both handheld and tripod conditions. If I had a front or back focus issue I would use the LensAlign ruler (or even perhaps the much maligned Spyder LensCal) to diagnose a problem. To date I have not ever done that.
This has been a much protracted post, but those are my experiences, but please do not think for one minute I am critising any of Michael Tape's products.