Cameras and lenses are never perfect.

Discuss cameras, settings, composition, or anything related to photography - cactus or other subjects.
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DaveW
Posts: 7376
Joined: Thu Dec 20, 2012 2:36 pm
Location: Nottingham, England/UK

Cameras and lenses are never perfect.

Post by DaveW »

See:-

http://www.lensrentals.com/blog/2010/03 ... ther-facts" onclick="window.open(this.href);return false;.

He also makes an interesting prediction:-

"As an aside, I think this is probably going to put the last nail in the Megapixel war’s coffin. The 4/3 companies have already said 12 Mpix is as far as they intend to go. I suspect the full-frame manufacturers are going to call a halt at 30 Mpix or so, just because there’s no sense in it: they’re already out-resolving the quality control of their best lenses."
DaveW
Posts: 7376
Joined: Thu Dec 20, 2012 2:36 pm
Location: Nottingham, England/UK

Re: Cameras and lenses are never perfect.

Post by DaveW »

Should have put their original article in first:-

https://www.lensrentals.com/blog/2008/1 ... ther-myths" onclick="window.open(this.href);return false;
DaveW
Posts: 7376
Joined: Thu Dec 20, 2012 2:36 pm
Location: Nottingham, England/UK

Re: Cameras and lenses are never perfect.

Post by DaveW »

The lens/camera focus problem is mainly noticed with wide apertures where depth of field is not large enough to cover any focus inaccuracy and particularly with wide angle rather than telephoto lenses. Some professionals in the past used to send in all their cameras and lenses into the makers to be "harmonised" so they were all in focus on those combinations. OK until they bought a new camera. In those days focus harmonisation adjustment was really only possible by the camera makers or repairers, not the photographer themselves. These days many new cameras have micro focus lens adjustment where you can adjust each lens for focus and the camera will remember that lens adjustment and automatically set the camera to it when you put the lens on:-

http://ophrysphotography.co.uk/pages/tu ... stment.htm" onclick="window.open(this.href);return false;

Of course the photographer needs to know how to set up and use a test target to use the adjustment or they will more likely put it out of focus rather than improve it.

http://www.the-digital-picture.com/Phot ... -Tips.aspx" onclick="window.open(this.href);return false;

An interesting quote from the Ophyrys link:-

"Expect some minor variations in focusing accuracy within each set of three test images, even though they were all taken at the same microadjustment setting. This is completely normal, and is due to the tolerances of the camera's AF system."

This is the very reason manual focusing using the human eye on the focusing screen is recommended for higher magnification macro work since at depths of field of a couple of millimetres or so autofocus is too inaccurate.

DaveW
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