The AFMA myth.

Started 5 months ago | Discussions thread
poppyjk Contributing Member • Posts: 756
Re: The AFMA myth.

Distinctly Average wrote:

First your test shots, maybe try with a sloped ruler and a proper target and you will see what the actual difference it makes. Why do you think the focus char tools and focus pyramids are not 6-8 feet deep? Maybe have a read of this -

I beg your pardon! Are you denying the reality that my sample photo focus changes between zero and -20 is about 6 feet? I purposely selected a scene at 175 feet with a slanted brick wall to provide compelling visual information which is more valuable and accurate than a 'sloped ruler' at 50X the lens focal length on the LensAlign tool.

I have used LensAlign MkII extensively as well as some other 'for sale' tools. In my experience using those tools with their inherent limitations often translates poorly to real world actual focus accuracy performance, especially with telephoto lenses. Nothing is more accurate than adjusting AFMA at the actual expected subject distance with a slanted foreground and background and from a tripod. If you have not tried it , I suggest you do.

You appear to be miss-understanding the whole point of the post and thread. AMFA can be a good tool. It is however given as advice based on very little actual evidence that there is a problem with AFMA. I have seen many times both online and in forums just how often it is offered as advice when other things are obviously amiss. If the basics are not correct, all AFMA is going to do is confuse things further, double so if AFMA is not fully understood.

I will ignore your dismissiveness. I understand and agree with most of the points that you make.

I completely disagree with "Some fail to even understand the “M” in AFMA stands for”Micro” and not massive. Even when the focus was off by meters, people still sat “do AMFA on all your lenses”. and "The adjustments only make a few mm difference in the focus point, but this can be enough to make things look terrible."  Are you really saying that a photo taken of a subject 200 feet away with a 600mm lens is only affected by a few millimeters when AFMA adjustments are made?

These statements are factually wrong for photos taken at distance in the real world. The reason for my post was to point out this inaccuracy so that those reading the thread would not be misled. The samples were included that actually show the differences are in feet not millimeters.

You appear to believe that there can not be several feet of difference in the focal point at long distance due to an AFMA problem. Do you actually believe that the several feet of distance shift is not represented factually and accurately in my sample photos?

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