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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Lens Image Circle...

Handy. Thanks for putting the list together. It will be invaluable as the 5K sensors hit the market.
 
Pawel Achtel said:
Matthew,

Great idea.

Your measurments, however, are different than what I measured here: http://www.reduser.net/forum/showpost.php?p=346908&postcount=52

One reason could be that I measured usable image circle before sharp falloff and loss of resolution. Any thoughts?
Click to expand...

This is a matter of great debate.. I totally agree with you about the focus fall off. I measured to light falloff. Not focus falloff.

If I was going to measure focus falloff, half of these lenses would be considered 16 format lenses, lol.
I'll leave it up to the user. These diameters are simply a measurement of where the lens stops reproducing light.

I would need a whole different list if I was going to measure the image circle based on focus falloff. This list is also personal reference for myself as I have been receiving many calls from people who want to buy a lens but want to make sure it will cover "5k". There is no quick answer other than for me to measure the image circle to the point where there is no longer an image. Perhaps in the future I will add a column for image diameter relative to focus. But then, that raises other questions including flatness of field.. Basically, you focus the lens to achieve maximum sharpness in the center of the image. But on some (most) lenses, you can rack through in either direction and bring the field of the image into focus. Too many variables.. That's why I just measured the diameter of light produced.
 
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