Am I asking too much?

Started Apr 4, 2013 | Discussions thread
MightyMike Forum Pro • Posts: 37,083
Re: Am I asking too much?

rondeann wrote:

MightyMike wrote:

You suggest you have many lenses that all need AF fine adjustment if i read this right. the obvious question is why haven't you got those lenses or the camera fixed? Why do people keep clearly defective equipment when they can just get it fixed? there are so many people since the possibility of AF adjustments that seem to have to have an adjustment on every lens, is it really that bad or are they all fooling themselves. i have a very large quantity of lenses, 13 AF lenses not for sale and none of them need any focus adjustment, i take pictures and if the pictures are in focus then its fine, if not its usually a limitation of the camera or the my fault. however there have been occasions where lenses have failed and i get them serviced, nothing in recent times though.

One of us may be an exception.  This post may answer that question.  I have 6 lens that I actually use.  Of those 2 require no adjustment and one of those is a prime.  The other 4 are zooms and require an adjustment and that adjustment is different from wide open to fully closed which makes it necessary to pick a mid point and hope for the best.

I can assure you i'm not the exception, i know many people across many brands who have many lenses that don't need AF adjustment, granted there are a few that do. if the problem is with the aperture adjustment its an issue that is less common than which focal length the zoom lens is at. some lenses do have a focus shift as you stop them down, its cause by a change in the not well corrected spherical aberrations, however this is rarely common in a modern lens.

You may be right.  I may be too lenient when I accept a lens or I may just be the norm.  I hope to find the answer to that with this post.

You are too lenient!

I must say that 13 lens with no required adjustment sounds exceptional.  Did you return a number of lens until you got one that required no adjustment?

I've had lenses that have failed in the past, a Sigma 10-20mm F4-5.6 that stopped focusing to infinity, ditto on a Pentax 10-17, both of which had been serviced and later on replace with different lenses. My first Sigma 100-300mm F4 had issues, these were serviced and then Sigma was nice enough to replace the lens entirely, the new one had a slight FF issue only noticeable at very close range shooting at F4.0 and 300mm, after i had them service the lens because i felt is focus had slowed that issue seems to go away (they took apart the lens and put it back together again). The only other lens i've ever had an issue with is the Tamron 17-50mm F2.8, the first copy was bad, replaced with another copy that also was bad, had bad intermittent focus issues, it took 10 months for the service to figure out the problem and fix it, part of that was my fault for not using the lens much and therefore not encountering the problem and then 10 months were it was perfect before i sold it for another lens. The only lenses i own that need focus adjustment are manual focus lenses when used in conjunction with focus trap, its a common issue that many manual focus lenses require a -10 or so adjustment to get focus spot on with focus trap, i see it more in telephoto lenses and fast lenses, however there are some lenses that just don't need this adjustment either.

The fact that manufacturers include the AF fine adjustment function would suggest that it may be "normal" for a lens to require some adjustment.

No! they included it so they wouldn't have to deal with as many service issues related to focus adjustment and because they realized they could implement such a feature. Not because its normal but because it cost less to implement than to fix small issues with some lenses.

I'd far rather have a perfectly working lens then one with a flaw that will cost lots of money if not fixed in the warranty period

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Mike from Canada
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