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Shooting 35mm on 6x7, lens equivalent for 55mm?


jamietea20

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So as the title suggests, I want to shoot 35mm Portrait on an Pentax 6x7.

 

But I don’t know which lens to buy to achieve the equivalent effect/ size of my subject as if they were shot on a 35mm film with a 55mm lens

 

So If I use a 55mm lens for the Pentax 6x7, but shooting with 35mm on it, will I simply get the subject, as they appear on a 35mm film with a 55mm lens?

 

Isn’t this the same as if I were to shoot on a 105mm lens for a 6x7, (which is close to a 53mm for a 35mm equivalent) and then crop to down a 35mm film size?

 

If not, what size of lens should I use, and why?

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Yes, if you cropped a 6x7 negative down to the size of a 35 mm negative then the image would be the same size as the same focal length on a 35 mm camera would make. Focal lengths are essentially constant; the angle of view from a given focal length will vary with the size of the film or digital sensor. One caveat: not all lenses of the same focal length will cover the same size of film or digital sensor. Most 55 mm lenses intended for a 35 mm camera wink vignette severely if used on medium or large format film at infinity.
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Thanks. No, I wasn't going to use a 55mm designed for a 35 on a medium format. I was going to use a 55mm designed for 6x7 but shoot 35mm film on it. So I can achieve a panoramic effect, but I also want to keep the portrait subject as if they were shot on a 55mm straight out of a 35mm camera, if that makes sense.

 

So in this case, there should not be any vignetting, I just want to make sure the subject size,

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That's not what AJG said. He makes perfect sense. A 55 mm lens for a 6x7 will still be 55 mm if you use 35 mm film in the camera. However the image circle is much larger than one designed for 35 mm film. Cropping 6x7 film to a strip the height of 35 mm film will be the same as if you used 35 mm film in the camera.
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Sho

Thanks. No, I wasn't going to use a 55mm designed for a 35 on a medium format. I was going to use a 55mm designed for 6x7 but shoot 35mm film on it. So I can achieve a panoramic effect, but I also want to keep the portrait subject as if they were shot on a 55mm straight out of a 35mm camera, if that makes sense.

 

So in this case, there should not be any vignetting, I just want to make sure the subject size,

SIMPLE. Shoot it on 6X7 with I20 and crop it down as a 35mm panoramic. .Mask with masking tape your viewfinder to width of 35mm film.

Edited by laurencecochrane
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Thanks. No, I wasn't going to use a 55mm designed for a 35 on a medium format. I was going to use a 55mm designed for 6x7 but shoot 35mm film on it. So I can achieve a panoramic effect, but I also want to keep the portrait subject as if they were shot on a 55mm straight out of a 35mm camera, if that makes sense.

 

So in this case, there should not be any vignetting, I just want to make sure the subject size,

 

It may or may not do what you want. 55 mm is a wide angle lens in medium format so there will be some distortions in perspective. That might be exactly what you're after, but it won't be the same as shooting a 55mm lens on a 35mm camera.

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I would caution that you do not use the or any 35mm "panorama" kit in a Pentax 6x7 (older model, 1969-onward) if it has the unmodified long film spool holders. If the adaptor is put into place with unmodified spool holders it will result in a jam, with the film requiring to be cut out and the spools destroyed. The modification has been done by others keen to use the panorama kit. Other problems include film slip that can damage the 6x7 shutter and inaccurate frame counting.
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Garyh | AUS

Pentax 67 w/ ME | Swiss ALPA SWA12 A/D | ZeroImage 69 multiformat pinhole | Canon EOS 1N+PDB E1

Kodachrome, Ektachrome, Fujichrome E6 user since 1977.

Ilfochrome Classic Master print technician (2003-2010) | Hybridised RA-4 print production from Heidelberg Tango scans

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It may or may not do what you want. 55 mm is a wide angle lens in medium format so there will be some distortions in perspective. That might be exactly what you're after, but it won't be the same as shooting a 55mm lens on a 35mm camera.

There is no "equivalent" factor when specifying medium format and full-frame lenses. 55mm is 55mm, f/2.8 is still f/2.8. There is some merit in comparing the field of view for various formats, including focal length equivalence, for educational purposes.

 

A 55 mm lens for medium format has a much wider image circle, capable of covering a 6x7 cm frame in this case. As such, it will have roughly the same FOV as a 28 mm lens on a FF camera - i.e., a wide-angle effect. Wide angle lenses tend to exaggerate perspective in the subject, but this is due to distance and geometry, not distortion. Distortion might also be present as pincushion or barrel distortion of straight lines.

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I would caution that you do not use the or any 35mm "panorama" kit in a Pentax 6x7 (older model, 1969-onward) if it has the unmodified long film spool holders. If the adaptor is put into place with unmodified spool holders it will result in a jam, with the film requiring to be cut out and the spools destroyed. The modification has been done by others keen to use the panorama kit. Other problems include film slip that can damage the 6x7 shutter and inaccurate frame counting.

 

Jam in the take up spool? How?

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There is no "equivalent" factor when specifying medium format and full-frame lenses. 55mm is 55mm, f/2.8 is still f/2.8. There is some merit in comparing the field of view for various formats, including focal length equivalence, for educational purposes.

 

A 55 mm lens for medium format has a much wider image circle, capable of covering a 6x7 cm frame in this case. As such, it will have roughly the same FOV as a 28 mm lens on a FF camera - i.e., a wide-angle effect. Wide angle lenses tend to exaggerate perspective in the subject, but this is due to distance and geometry, not distortion. Distortion might also be present as pincushion or barrel distortion of straight lines.

 

Sorry, I probably should not have used the term "distortion" since that has a particular meaning when it comes to lenses, but what I was talking about is what you referred to as "exaggeration" when it comes to perspective.

 

FOV is not just a pedantic discussion in this case. It's central to what the OP wants to do. They want to expose the 35mm film at a much larger frame size that what would be exposed in a 35mm camera.

 

55mm is still 55mm but it's not a normal or standard lens they way he intends to use it, - not like it would be on a 35mm camera.

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If I understand it correctly, the OP wants to shoot a panoramic frame, with a portrait subject in the central area. I think what he proposes will give him that. The central part of his frame will have normal perspective: for that area, the 55mm lens is a normal lens. The areas at the left and right will start to look more unusual, just because of increasing subject distance; real perspective, in a view we just aren't used to seeing. I don't think 55mm will be extreme though. It could be a good way to include an interesting location with his portrait.

Just for fun, you should get your subject to lie across the whole frame, or maybe take a group shot of three people.

It's worth investigating what Silent Street said about the 35mm holder; if it's a serious problem I'd expect it to be mentioned on user's fora (maybe elsewhere on photo.net); but if in doubt you can always shoot it on 120 film and crop it. Good luck!

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If I understand it correctly, the OP wants to shoot a panoramic frame, with a portrait subject in the central area. I think what he proposes will give him that. The central part of his frame will have normal perspective: for that area, the 55mm lens is a normal lens. The areas at the left and right will start to look more unusual, just because of increasing subject distance; real perspective, in a view we just aren't used to seeing. I don't think 55mm will be extreme though. It could be a good way to include an interesting location with his portrait.

Just for fun, you should get your subject to lie across the whole frame, or maybe take a group shot of three people.

It's worth investigating what Silent Street said about the 35mm holder; if it's a serious problem I'd expect it to be mentioned on user's fora (maybe elsewhere on photo.net); but if in doubt you can always shoot it on 120 film and crop it. Good luck!

 

Yes, a 55mm 6x7 lens is about a 28mm on 35mm, so I doubt it will be much of a difference.

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