Does 0.8x 92TCC Cover 645 Digital Format (44mm x 33mm)?


yliu410@...
 

Hi Roland,

I‘m aware the imaging circle in 92TCC's specification is 40mm, which means it should only cover 135 full film, a 36mm x 24mm sensor. But I can't keep thinking about how it would work in a 44x33 format. It may sounds a bit greedy but I did find it possible on multiple lens / telescopes that was designed for 135 format (including several telephoto lens, a 5 inch astrograph with a 0.72x and 1.4x 135 format reducer/flattener).

I'm currently using a Traveler and the 67 flattener on a 645 digital format camera and get really nice results, if the 0.8x could work on it too would be even better! :D

Regards,
Yitao


Roland Christen
 

The 92TCC has light falloff (vignetting) in the corners of a 36x24mm sensor. It does not have a large enough opening to fully illuminate the 44 mm circle of a full format 35mm camera. You can flat field and get a reasonable image that looks good.

For an even bigger 44x33mm format you would need a 55mm clear aperture reducer, so our 92 reducer will not be big enough for that size chip.

Roland

-----Original Message-----
From: yliu410@...
To: main@ap-ug.groups.io
Sent: Wed, Jan 5, 2022 11:09 pm
Subject: [ap-ug] Does 0.8x 92TCC Cover 645 Digital Format (44mm x 33mm)?

Hi Roland,

I‘m aware the imaging circle in 92TCC's specification is 40mm, which means it should only cover 135 full film, a 36mm x 24mm sensor. But I can't keep thinking about how it would work in a 44x33 format. It may sounds a bit greedy but I did find it possible on multiple lens / telescopes that was designed for 135 format (including several telephoto lens, a 5 inch astrograph with a 0.72x and 1.4x 135 format reducer/flattener).

I'm currently using a Traveler and the 67 flattener on a 645 digital format camera and get really nice results, if the 0.8x could work on it too would be even better! :D

Regards,
Yitao