Pentax 67 Lenses on Canon 5d IV

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joswhite1991

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Hey guys,

So I have a 5D IV and Pentax 67.

I would like to use my Pentax lenses on my 5d IV. I brought the standard adapter online that you can find everywhere, although it works nicely it is super long and creates way too much magnification on my wide lenses which I really do not like.

My question is does anyone know of a way of getting rid of this magnification? I have looked at lots of different combinations of adapters online to see if I can get the lens closer to the camera but have had no success as all the adapters/combos are very long.

I was even looking at potentially cutting my current adapter in half and have the aluminium welded back together to make it shorter.

I have loads of lenses for my 67 so thought I would try and find a way of making this work before spending any cash on film lenses. Please don't ask me why I'm not using digital lenses. I love the look of the film glass and it is what it is haha.

Thanks in advance!
 
joswhite1991 said:
... creates way too much magnification on my wide lenses which I really do not like.
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It's not "creating" magnification, just using a smaller section of the image circle. That's what happens when you fit a lens for one format on a body for a smaller format.

A focal length reducing lens might work but it may reduce the sharpness of the wide angle more than you want...

View: https://www.youtube.com/watch?v=U9fFYAlv_zQ
 
Surely they are long for a reason, to accommodate a much larger lens mount to a smaller body. If the adaptor could be made shorter, wouldn't it???

The penalty is not that the magnification/difference in focal length to sensor size factor is unacceptable for you i.e. a crop factor!
 
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The Pentax 67 is a medium format body, so lenses will be longer focal length for any given field of view when compared to a standard FF body.

Look on the Pentax lenses you have and let us know what focal lengths you see. At a guess, I'd expect a "normal" lens for the Pentax 67 to be around 90mm or so. A 90mm lens on a FF body, like the 5D IV, would be considered a short telephoto.
 
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Box Brownie said:
Surely they are long for a reason, to accommodate a much larger lens mount to a smaller body. If the adaptor could be made shorter, wouldn't it???

The penalty as you not that the magnification factor is unacceptable for you.
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Yeah absolutely my thought was just hoping to hear something different :(
 
AndrewFlannigan said:
It's not "creating" magnification, just using a smaller section of the image circle. That's what happens when you fit a lens for one format on a body for a smaller format.

A focal length reducing lens might work but it may reduce the sharpness of the wide angle more than you want...

View: https://www.youtube.com/watch?v=U9fFYAlv_zQ
Click to expand...

Exactly - the 'standard' 105mm lens on the 67 is a still 105mm on your 5D
 
AndrewFlannigan said:
It's not "creating" magnification, just using a smaller section of the image circle. That's what happens when you fit a lens for one format on a body for a smaller format.

A focal length reducing lens might work but it may reduce the sharpness of the wide angle more than you want...

View: https://www.youtube.com/watch?v=U9fFYAlv_zQ
Click to expand...

Interesting, thank you for the info. I shall look into this.
 
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I hear the expression "film glass" a lot these days. Can somebody explain what the difference is in the finished picture? I've got a load of film lens and I've used a few but never saw any real difference apart from them not being as good as modern lens. Really courious what I'm missing?
 
AndrewFlannigan said:
Indeed - that's the key to his misunderstanding.

Rob was correct - 105mm is 105mm - unless you're using trick measuring tape.

The effect that Jos reported is cropping - end of story.
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Yes, cropping as I said but you did not include in your quotation clip.

Having said that unlike my mFT 300mm lens being the FoV equivalence of 600mm in FF terms it is not clear in the case of the OP's intended usage what effect (is stated?) does the adaptor introduced? Why, AFAIK, as the adaptor has no internal lenses but the rear most element of the 105mm lens is pushed forward away from the plane of the sensor compared to when the 105mm is used on the 67 body.

Isn't that increased distance an added 'aspect' in the crop factor calculation???
 
Box Brownie said:
No! as covered here https://photographybay.com/2016/02/06/understanding-medium-format-crop-factors

There is a crop factor to take account of.

PS the above is a direct FoV equivalence what you need is, because the adaptor increases the distance to the focal plane, what do the adaptor manufacturers say about the change in focal length they are introducing???
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A regular adapter doesn’t change the focal length of anything.

The adapter‘s (only) job is to maintain the correct distance between the back of the lens and the focal plane (the ‘Register’ - 84.95mm for Pentax 67) when mounted on a body with a shorter Register Distance (44mm for Canon EF).

If you take a a Canon 24-105mm f4L, mount it on the 5D and set it to f/8 and 105mm, you would pretty much get the same image as an standard Pentax 67 105mm lens at f/8 adapted to the same 5D.

The 5D sensor only ‘sees’ a smaller portion of the image than medium format film, though.

Cutting down the adapter, or using a shorter adapter would just mean the lens could not focus on the 5D’s sensor.

The same goes for my Mamiya 645 lenses. In terms of angle of view, the Mamiya Sekor 55mm would behave like the Sony FE 55mm ZA lens I use already on my Sony FE bodies

The Speed Booster in the video contain glass elements and does change the optical properties of the lens Being adapted.
 
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Box Brownie said:
Yes, cropping as I said but you did not include in your quotation clip.

Having said that unlike my mFT 300mm lens being the FoV equivalence of 600mm in FF terms it is not clear in the case of the OP's intended usage what effect (is stated?) does the adaptor introduced? Why, AFAIK, as the adaptor has no internal lenses but the rear most element of the 105mm lens is pushed forward away from the plane of the sensor compared to when the 105mm is used on the 67 body.

Isn't that increased distance an added 'aspect' in the crop factor calculation???
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I’d have thought it was pushed forward to exactly the same place, otherwise the lens wouldn’t focus.

Simple optics or I’m daft.
 
Box Brownie said:
but the rear most element of the 105mm lens is pushed forward away from the plane of the sensor compared to when the 105mm is used on the 67 body.
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As Rob notes (above), the adapter places the rear element of the lens at the same distance from the sensor in the Canon 5d as it would be from the film, when fitted to the Pentax 67. It has no other function or capability in this context.
 
AndrewFlannigan said:
As Rob notes (above), the adapter places the rear element of the lens at the same distance from the sensor in the Canon 5d as it would be from the film, when fitted to the Pentax 67. It has no other function or capability in this context.
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Ah! sorry I missed that....thanks for the clarification:)
 
joswhite1991 said:
Please don't ask me why I'm not using digital lenses. I love the look of the film glass and it is what it is haha.
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I think you’re being sucked in by ‘fashion’ rather than a factual practical view.

Of my shiny EF lenses that work perfectly as ‘digital’ on all my canon cameras (including a film camera, crop and full frame dslr and mirrorless) are the 70-200 2.8 (1995) and 135 f2 (1996)
I’ve also owned 200 2.8 (1991) 135 2.8 (1987) nifty 50 (1992) and the 85mm 1.8 (1987)

And I bet you’re thinking ‘that’s not what I mean’. Because the idea of ‘film era’ in your head means manual focus and inconvenient which creates ‘magical’ rather than the factual definition of lenses that were designed to fit cameras that shoot film.

The only lenses I’d describe as genuinely ‘digital era’ are the new generation ones that have actual optical flaws that communicate those flaws to the processing software to be edited out. Everything else is just a lens.

But horses for courses.
 
The only thing I recall (vaguely) about film era lenses was the 'debate' about the difference(s) between Japanese made lenses and Carl Zeiss/Carl Zeiss Jena.

IIRC it was said that there was a discernable difference on contrast and warmth/cool look, with even subtle differences between CZ and CZJ ones.

The Japanese lenses were seen as slightly lower contrast and 'warmer' compared to the European lenses.

Again more latterly IIRC, that lens coatings had been improved(?) especially rear element coatings due to different reflectivity of sensors compared to film emulsions.

So any choices of lens based on the "look" of the image comes under YMMV
 
For me, the biggest difference ignoring AF etc is that older lenses are usually less sharp, have a bit more flare, lower contrast, more coma etc than a good recent lens. But from the way in which the question has been asked, I'm not sure the OP will necessarily notice the difference.
 
swanseamale47 said:
;DI hear the expression "film glass" a lot these days. Can somebody explain what the difference is in the finished picture? I've got a load of film lens and I've used a few but never saw any real difference apart from them not being as good as modern lens. Really courious what I'm missing?
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I have some film era lenses and I've taken a lot of pictures with them on digital bodies.

I think some film era lenses can just give a different look, maybe less clinical or transparent than a more modern lens, more... character :D Maybe more of all the things that have largely or at least to an extent been eliminated or reduced from good lenses of recent times are there to a greater extent with older lenses. They may be less sharp, the bokeh may be more more nervous, the fall off away from the centre may be more pronounced, they may have more vignetting, ca, distortion and all the rest, they may well have less good coatings and they may be more susceptible to flare. All these things can just add up to a different look.

Film lenses vary, for example my Nikon AI-S and some of my Minolta Rokkor lenses probably give the most modern look of my film era lenses and the lenses which can be more extreme in their distance from that look are probably the older ones.

There's also the tactility and use to be considered as some old lenses are just gorgeous tactile things to use.
 
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