[stevebrot]

What he is calculating is the radius of the image circle which is 21.633. 21.633 x 2 yields an image circle of 43.266mm. The Sony FF sensor measures 23.9 x 35.8mm which requires an image circle of 43.044mm. You have a tolerance of 0.222mm. Plenty....

Yes, what he is calculating is the radius, though he explicitly stated that it was the image circle. I don't know where the assumption came from that "image height" = radius of the image circle, but I find it somewhat convenient if one is trying to make the point for a FF lens. More likely (as pointed out in multiple comments above), this is evidence of a 70-210 APS-C lens design that never made it to market.


Steve

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Last edited by stevebrot; 10-07-2012 at 08:59 AM.

[Winder]

Yes, what he is calculating is the radius, though he does seem to have a bit of a problem with decimal points. I don't know where the assumption came from that "image height" = radius of the image circle, but I find it somewhat convenient if one is trying to make the point for a FF lens. More likely (as pointed out in multiple comments above), this is evidence of a 70-210 APS-C lens design that never made it to market.


Steve

If you look at Canon patents for FF glass, you see they list the image height. Image height is always half of image circle in the patents.
If you look at other Pentax patents for DA lenses that have been produced you see that the image circle is 28.84mm. This lens was designed with a FF image circle (43.13mm) in a focal range that is standard for FF lenses. If it had been designed with a image circle of 28.84mm I would agree that it is an APS-C lens.

If Canon starts filing patents for MF glass, then I think it is safe to assume that Canon is paying someone to design MF glass. If Pentax starts filing patents for FF glass, then I think it is safe to say that Pentax is paying someone to design FF glass. Pentax may not make the lens, but the fact that they are putting resources into the project is a good sign.

If you see Pentax design a lens with an Image Height of 34.85mm then you know that will cover a full 645 frame (56x41.5mm) and when you see them design a lens with an image height of 27.60mm you know it will only cover the 645D (44x33mm).

[forestskier]

I hope this means the Pentax has some hope to meka FF camera.

[felixkh]

And hey, what about some love for us film shooters? Canon and Nikon never abandoned their film users. I may be wrong, but I believe both companies still make a film body, and of course all their Fx/EF lenses can be used on film.
.

Canon did abondon the orignl film shooters who used the FD mount before they decided to go AF and changed the mount to EF.

[KungPOW]

Canon did abondon the orignl film shooters who used the FD mount before they decided to go AF and changed the mount to EF.

People seriously need to let this go.

This was over 25 years ago.

This was a required change that brought Canon to the market share it now has.

Unlike the Nikon N mount, and the Pentax K mount, the Canon FD mount would not allow for the changes needed to move into the world of autofocus, and electronic lens control.

Just looking at market share, obviously Canon made the right choice at the right time.

[ElJamoquio]

People seriously need to let this go.

It was a response to the claim that Canon had never abandoned their film shooters. It's not like the guy was starting a new thread... someone had stated something wrong and was corrected.

[Blue]

It was a response to the claim that Canon had never abandoned their film shooters. It's not like the guy was starting a new thread... someone had stated something wrong and was corrected.

True and Canon had to do it to make af viable whereas Pentax and Nikon had a good mount already in place. Plus, Honeywell hammered Canon's competition with a huge AF lawsuit that creamed Minolta and impacted some others.

[felixkh]

People seriously need to let this go.

This was over 25 years ago.

This was a required change that brought Canon to the market share it now has.

Unlike the Nikon N mount, and the Pentax K mount, the Canon FD mount would not allow for the changes needed to move into the world of autofocus, and electronic lens control.

Just looking at market share, obviously Canon made the right choice at the right time.

Yes I know that they changed the mount so that thy are where they are now, but I was responding to the other user I quoted that said Canon never changed the mount.

I too was a Canon film user in the days of F1, A1, AE1 camera bodies and at that point in time I felt Canon just wanted to make more money from its user base. But I also had a K mount Cosina CT1S and a Chinon CP 7m body with some K mount lenses and that was when I fully switched to Pentax as I could still use the existing k mount lenses I already had.

Peace