[philbaum]

“This Lens is Soft”…. Canon Rumors

This website features two articles by Roger Cicala from LensRentals.com, the first 2008 article and a 2010 followup.

I think it ought to be required reading for every new SLR owner.

If both 2008/2010 articles have already been referenced on PF, i apologize and perhaps a moderator should delete this thread.

He's a big proponent of AF fine adjustments and mentions the K20 in the older article. Considering this article, i wonder why every SLR, including entry level ones don't have the fine adjustment software built in. Its not a luxury, its a necessity.
IMO, Pentax should take the lead and have fine aF adjustment in KR and Kx entry level models as well. It costs nothing extra to include that function in the camera.

[Rondec]

I agree that this should be an option, but it really does take some knowledge in order to evaluate how to adjust an individual lens. People buying an entry level camera are more likely to screw things up than to improve the situation.

That said, particularly with an f1.4 lens, I wouldn't buy a camera without this feature.

[philbaum]

I agree that this should be an option, but it really does take some knowledge in order to evaluate how to adjust an individual lens. People buying an entry level camera are more likely to screw things up than to improve the situation.

That said, particularly with an f1.4 lens, I wouldn't buy a camera without this feature.

well, i agree that it involves some complexity. Mfr should leave this option off as a default and for total automatic operation. But i think AF adjustment is less complex than choosing different apertures and shutter speeds - which many of us take for granted.

I keep 3 magnetic signs, of similar font size, on the front of my refrigerator in a horizontal row. Setting myself about 15 ft away and at an angle of 45 deg about, I've been able to check a lens before going out for an assignment in a few minutes and dial in an adjustment.

When one contemplates the alternatives - e.g sending a lens and cam combination in for 3 weeks of adjustment at a service center, that doesn't pay for the company or the individual. I wouldn't buy any camera without it, my last 2, K20 and K5, have had it. The first SLR maker who includes this facility up and down the models, will probably see some increase sales than those mfr who refuse to make this facility available to everyone.

[rawr]

Those articles have been referenced in PentaxForums many, many times, but another mention would certainly do no harm.

Especially given the frequency in which people complain about BF/FF issues, and the wrong conclusions they often draw about what is going on.

On a related note, similar to what Rondec is saying, somewhere there should also be a standard text or required reading about the proper way to do AF testing. Time and time again the AF 'problems' raised by people are the result of their poor AF testing procedures, leading them to see the problem wrong, and apply the wrong fixes too.

Perhaps every new SLR user with a camera that has an AF adjustment capability should also be required to buy some credible and standardised AF testing rig (eg like the Datacolor Spyder LensCal lens calibrator) in order to ensure they don't make a mess of their AF adjustments.

[kiwi_jono]

I agree this is a significant problem. I use a K-x and have resorted to debug menu way of fine tuning autofocus. And boy did it make a difference for me - especially with the faster lenses of course. I shoot a lot with manual lenses and focus adjustment is still important to me for the focus confirm.

My only problem with the K-x is that there are differences from lens to lens and I have only one correction setting for all lenses but thats more manageable at least (at times I have tweaked a bit if I am using one lens more than others).

Also agree that testing focus has to be done in the right way - but is not hard once you have done it a few times.

[stevebrot]

On a related note, similar to what Rondec is saying, somewhere there should also be a standard text or required reading about the proper way to do AF testing.

Indeed. That and a general tutorial on the practical limits of AF.


Steve

[MegaPower]

I have read more than one actricle with the same idea.

I agree on the +focus on camera and -focus on lens will result on the perfect result.
Thus, you need a camera which can adjust minor focus to get the best result. Who knows the lens you got is a front/back focus lens in the micro world?

[philbaum]

I have read more than one actricle with the same idea.

I agree on the +focus on camera and -focus on lens will result on the perfect result.
Thus, you need a camera which can adjust minor focus to get the best result. Who knows the lens you got is a front/back focus lens in the micro world?

The current mechanical bayonet approach to DSLR lenses/bodies was born in the film camera days, when there was much more forgiving film instead of a digital sensor. The article casts doubt on the ability of the current system to provide interchangeable lenses to the tolerances required by today's sensors.

Ricoh's calibrated gxr modules are one solution, but expensive. The Fuji x100 is another answer. Perhaps there is another solution as well: a hi tech universal mount which is self calibrating or as the article suggests - lenses that self calibrate.

Or how about a smart body which self calibrates each lens to its sensor location. Instead of using an SR mounted sensor, why not use that same technology for calibration instead of SR. Frankly, i would rather have a sharp lens than SR.

[Lowell Goudge]

Phil. Do you mean to say we accepted less sharp images on film?

As to the issue when I learned on film we were taught to stop down to correct for minor focus errors. Unless you need to shoot F1.2 on a 50mm or F2.8 at 400 mm stopping down solves most bf/ff issues

[philbaum]

Phil. Do you mean to say we accepted less sharp images on film?

As to the issue when I learned on film we were taught to stop down to correct for minor focus errors. Unless you need to shoot F1.2 on a 50mm or F2.8 at 400 mm stopping down solves most bf/ff issues

I mean three things:
a. The technology of film cameras was less demanding - film being .0056" thick which i've been told makes a greater thickness available for absorption than a sensor's plane. The author of the report says as little as .0008"lens misalignment can cause image problems which are detectable in today's high resolution digital technology.

b. I wasn't that involved in film cameras when i was younger, but i remember the more serious photographers looking at slides spread out over a light box and using a magnifying glass. Today we used our computer monitors to magnify images to 100%, 200% or more.

c. Many people are printing less often, but when they do print - they are printing larger on average than they used to. Printing costs have gone down relatively. When i put something on a wall today, 12" x 18" is the minimum i want to see, 16 x 24 is nicer, 20x30 is large, but not the largest i've done. (So yes, i think standards by photographers and customers have gone up, most likely.

Lowell, you've been into photography longer than i, so if any of my opinions seem like they may be weak, please speak up, its not like i have many facts to base my opinions on.