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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 :)

Crop factor for Pentax 67 lenses?

Arnold,

Not sure what you´re asking for. A lens does not have a crop factor. E.g. 50mm will always remain 50mm. You´ll have to consider that these MF lenses have been calculated for a much greater sensor size of 54x70mm and won´t be as sharp as dedicated cine or "FullFrame" DSLR lenses. They might look very nice though, as always depends on the project.

Cheers, Ulf
 
Thank you. This is why I have put "crop factor" in quotes. Substitute "crop factor" for the term of your choice or, even better, give me the correct term and I'll use it to ask the question again. Do you truly not understand what I'm asking?


Ulf Krentz said:
Arnold,

Not sure what you´re asking for. A lens does not have a crop factor. E.g. 50mm will always remain 50mm. You´ll have to consider that these MF lenses have been calculated for a much greater sensor size of 54x70mm and won´t be as sharp as dedicated cine or "FullFrame" DSLR lenses. They might look very nice though, as always depends on the project.

Cheers, Ulf
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Arnold,

Sorry, I did not intend to offend you, in fact I did not understand your question. I hope to get it right this time, if you like to know what a standard lens is like the 50mm for FF DSLR it will be 90mm for 6x7. You take the diagonal of your frame which is perceived as "normal" - but also have to consider the aspect ratio which usually is much wider for film or video. In case you meant the image circle as a "crop" it will vary from lens design to lens design but it will at least cover (more than) 90mm. Putting that "normal" 90mm Pentax on an Epic will give you the same "tele" viewing angle like any other (cine) 90mm lens.

Cheers, Ulf
 
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In Ulf's defense, I'm not sure I understand what you're asking for either, Arnold. Lenses don't have crop factors, but as these Pentax lenses are designed for Medium Format cameras, they will project a larger image circle than a lens designed for a 35mm camera. Generally speaking anyway, these lines really blur at longer focal lengths as longer lenses tend to project larger image circles.

So if you have a 75mm Pentax MF lens and put it on an EPIC, you're going to get the same angle of view that you would have if you put any other 75mm lens on the EPIC.

Now if you want to relate crop factors between the EPIC and a Pentax 67 series camera, that's another matter. It varies between the various models, but the maximum frame dimensions on the Pentax here are 70mm x 60mm. Maximum frame width on the EPIC Dragon is 30.7mm. So in landscape, the Pentax is 2.28X wider or the Dragon is a 0.44X crop of the Pentax 67.
 
Unfortunately, I don't know how to ask the question so I'll just try to figure out what the image will look like if I tried it.


Jeff Kilgroe said:
In Ulf's defense, I'm not sure I understand what you're asking for either, Arnold. Lenses don't have crop factors, but as these Pentax lenses are designed for Medium Format cameras, they will project a larger image circle than a lens designed for a 35mm camera. Generally speaking anyway, these lines really blur at longer focal lengths as longer lenses tend to project larger image circles.

So if you have a 75mm Pentax MF lens and put it on an EPIC, you're going to get the same angle of view that you would have if you put any other 75mm lens on the EPIC.

Now if you want to relate crop factors between the EPIC and a Pentax 67 series camera, that's another matter. It varies between the various models, but the maximum frame dimensions on the Pentax here are 70mm x 60mm. Maximum frame width on the EPIC Dragon is 30.7mm. So in landscape, the Pentax is 2.28X wider or the Dragon is a 0.44X crop of the Pentax 67.
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Since Pentax 67 has bigger frame than fullframe or any other digital camera on market you wont have any hassle in future with lenses.If it was APC/M43/APSH/s35 glass it would have chance to vignette on Dragon.
 
No doubt. I reckon I'll buy a 67 lens, put it on and try to figure out what the focal length looks like on the monitor.
 
I understand completely your question but I don't know what the answer is. I also however think you are using the wrong term "crop factor" as you can't say it in another proper way.

What I will do is put it on the camera and then put another lens and compare it.

Then you'll know.

I had the same question as you.

I did that with 2 lenses from a Hasselblad I own, the 503cx and the lenses were 120mm macro and the 59mm FLE.

The results were so fantastic I bought another set to use it in my 3d shootings.
 
Arnold F. said:
What would my "crop factor" be when using Pentax 67 lenses?
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Are you asking what the multiplier is?

e.g. Canon 50mm 1.2 lens on an APS-C sized sensor has a field-of-view of 80mm lens since the multiplier is 1.6x
 
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Arnold, let's see if this helps:

The SMC Pentax 90mm Takumar will give you the same field of view on your scarlet as a Leica 90mm Sumicron or a Tamron SP 90mm Macro, or a Hasselblad 90mm XPan lens. So it will be a moderate telephoto, not the normal lens that it is on the Pentax.

The SMC Pentax 67 45mm Takumar will have the same field of view as a Nikon P 45mm Ai-S, or a Minolta 45mm Rokkor, or the 45mm position on an Angineux DP 30-80mm zoom. So it will be pretty much a "normal" lens, just a shade wider than a 50mm, not the wide angle it is on the Pentax.

The SMC Pentax 200mm Takumar will give you exactly the same field of view on your Scarlet as a 200mm Nikkor, or a 200mm Canon lens, or the long end of a Zeiss 70-200mm lightweight zoom.

Does that make things any clearer?
 
Arnold F. said:
No doubt. I reckon I'll buy a 67 lens, put it on and try to figure out what the focal length looks like on the monitor.
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Focal length won't look any different than if you put any other lens of the same focal length on the camera. If you buy a 100mm Ultra prime, or a 100mm Canon EF, or a 100mm Voigtlander, or a 100mm Pentax 67 series or a 100mm Fujinon broadcast 2/3" lens.. etc.. They all will give the exact same angle of view, because they are a 100mm focal length. End of story.

Now, each lens design can vary so there are always differences in aspects like breathing, spherical distortion, micro-focus, field illumination, sharpness, color rendition, flaring and more. That's why a Cooke S4 has a different "look" than a Canon CN-E prime or a Cine-Xenar and so on.

And if you're trying to relate crop factors or angle/ field of view between the two camera, I already gave those crop factors above in my previous post. At least between EPIC Dragon and the Pentax 67 series cameras. In a nutshell, to match the two cameras' angle of views, you have a 2.28X multiplier. So a 35mm lens on Dragon would look just like an 80mm lens on the Pentax 67.

D Fuller said:
Of course it is. I'm hoping that we can help people to see that by coming at it from the other direction.
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I don't know. I think I've tried to explain it from every which way imaginable and it's like a lost cause much of the time. And we can blame a lot of the DSLR and consumer camera makers to. Their incessant desire to quote things in reference to crop factors or "equivalent" focal lengths in regards to 35mm FF systems is often infuriating and just a total dumbass way to go about this stuff. Now the entire industry tries to think in these terms and it just creates far more confusion than any form of actual understanding.
 
It's simple: the focal length of the lens is a physical measurement and doesn't become any other focal length just because it is put onto different cameras with different sized sensors. A 75mm lens built for a Super-8 camera, an APS-C camera, a 35mm movie camera, a 65mm 15-perf IMAX camera, a 6x7 camera, and 8x10 camera... they all have a 75mm focal length, and they would still be a 75mm lens when switched around and mounted onto each other. Because the focal length is a physical measurement of the lens, just as if you had a 2" length of pipe and stuck it one various objects, it always remains a 2" length of pipe. So people should stop confusing the issue by asking "what focal length does my 75mm lens become when I switch it to x camera?" It can't change its physical dimension by being put onto different cameras.
 
Jeff Kilgroe said:
I don't know. I think I've tried to explain it from every which way imaginable and it's like a lost cause much of the time. And we can blame a lot of the DSLR and consumer camera makers to. Their incessant desire to quote things in reference to crop factors or "equivalent" focal lengths in regards to 35mm FF systems is often infuriating and just a total dumbass way to go about this stuff. Now the entire industry tries to think in these terms and it just creates far more confusion than any form of actual understanding.
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I hear you. IMO, the concept of "crop factor" has done more to stunt people's understanding of lenses than just about anything else I can think of. I grew up shooting 35mm, 6x6, 4x5, 16 & 35mm film, and oh yes, occasionally 8x10 and 35mm half-frame. It was never a problem to understand field of view equivalencies between any of those systems; all you really needed to know was what focal length gave you a "normal" field of view for the format.


But every once in a while I have to wade into one of these discussions just to see if I can slay a dragon or something... ;)
 
D Fuller said:
I hear you. IMO, the concept of "crop factor" has done more to stunt people's understanding of lenses than just about anything else I can think of. I grew up shooting 35mm, 6x6, 4x5, 16 & 35mm film, and oh yes, occasionally 8x10 and 35mm half-frame. It was never a problem to understand field of view equivalencies between any of those systems; all you really needed to know was what focal length gave you a "normal" field of view for the format.


But every once in a while I have to wade into one of these discussions just to see if I can slay a dragon or something... ;)
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David,

Same here, coming from stills photography I´ve been using a variety of formats as well and feel familiar with the topic. I think the "problem" is the perceived conjunction of focal length and viewing angle which clearly does not exist. What´s actually surprising for me is that Scarlet / Epic users are being trapped as the use of the different resolutions is done by cropping the sensor size and should lead to a realistic approach to perception of focal lengths.

As nobody really came up with something new after my response and being flamed immediately can anybody shed some light on what might have been the question since the OP stated he is going to buy a Pentax lens to get his answer??

Cheers, Ulf
 
Ulf Krentz said:
David,

Same here, coming from stills photography I´ve been using a variety of formats as well and feel familiar with the topic. I think the "problem" is the perceived conjunction of focal length and viewing angle which clearly does not exist. What´s actually surprising for me is that Scarlet / Epic users are being trapped as the use of the different resolutions is done by cropping the sensor size and should lead to a realistic approach to perception of focal lengths.
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You would think that would help, and perhaps for many it does. For that matter, with so many coming from Mk 3s and 7Ds that would seem like it should be instructive.

Ulf Krentz said:
As nobody really came up with something new after my response and being flamed immediately can anybody shed some light on what might have been the question since the OP stated he is going to buy a Pentax lens to get his answer??

Cheers, Ulf
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One of the confusing things about these "crop factor" discussions is that it always has to be in relation to something -- FF 35 is the most common, but he never made that clear. That's why I tried to answer in terms of lenses alone. But, as is often the case, I think David Mullen might have the best way to clarify the concept.
 
Totally agree with all the crop factor frustrations. As the saying goes, a 50 is a 50 is a 50. That said, as an owner of a fully modded set of Hasselblads, i have found their bokeh to be quite unique and alluring. They have their own personailty, quite different than my Contax, even on the same sensor.
 
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