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Anyone try a Pentax 67 105f2.4 on any fullframe DSLR?
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PostPosted: Mon Jan 15, 2018 3:15 pm    Post subject: Reply with quote
Pancolart wrote:
blotafton wrote:
I don't know if it will make anyone wiser but here is a comparison made by Tim https://www.flickr.com/photos/tb303/2884286769

Hasselblad Planar 80mm 2.8 vs EOS 5D Distagon 35mm 1.4.

Again photos says more then thousands words Wink, nice share!


However, the topic here is "Anyone try a Pentax 67 105f2.4 on any fullframe DSLR?",

Do not expect any 67 lens to give any different results on FF than same focal length FF lens on FF. There's no 67 camera in that statement!

Some expect 67 lens to give on FF 1/2x fov as same focal length FF lens on FF camera. That's incorrect.

67 lens will, however, give 2x fov on 67 camera, than same focal length lens on FF. Here, and in the example linked above. Comparing results from two cameras.


PostPosted: Mon Jan 15, 2018 4:46 pm    Post subject: Reply with quote
tb_a wrote:
Sciolist wrote:
Abbazz wrote:
All this nonsense...


I'd agree Abbazz.

However, while it continues with people on the internet, it's source is not from them from what I've perceived. ...


I agree to both of you.

Many of the modern digital cameras with smaller than 24x36 sensors have the focal length field of view equivalence already marked on their lenses. E.g. my old Minolta Dimage 7i with 8.8 x 6.6 mm sensor doesn't even state the actual focal length but only "28 - 200 mm" which is absolute nonsense. Also my Ricoh GXR APS-C modules are sold as 28mm (actual 18.3mm) and 50mm (actual 33mm) ones and there are many others as well. Therefore the source is undoubtfully the camera industry itself.


Thanks for providing some real world info tb-a. Ruminations are all well and good, but evidence as you supply is better.


PostPosted: Mon Jan 15, 2018 9:50 pm    Post subject: Reply with quote
Sciolist wrote:
I'd agree Abbazz.

However, while it continues with people on the internet, it's source is not from them from what I've perceived. The source, I suspect, were marketing departments trying to help film photographers transition to digital. I suspect that if the marketing guys had spoken to the engineering department, we may indeed have been using field of view as the common comparison. Instead, and only a gut feeling, the marketing guys spoke to each other about how best to explain these new sensor sizes to film photographers, and came up with 'equivalence'. This in turn was promoted to retail and camera reviewers as talking points, who in turn talked about it on the internet. Taking this lead, it became the common comparison on the internet.


You are indeed right. The source is undubitably from camera industry itself. But the marketing plot has been popularized on the internet and its use has become widespread with the help of internet forums. And the notion of "aperture equivalence" is pure internet stuff.

Sciolist wrote:
It would be interesting to see what comparators were used, if any, in the film world back in the day, when a new film size came on the market.

tb_a wrote:
I agree to both of you.

Many of the modern digital cameras with smaller than 24x36 sensors have the focal length field of view equivalence already marked on their lenses. E.g. my old Minolta Dimage 7i with 8.8 x 6.6 mm sensor doesn't even state the actual focal length but only "28 - 200 mm" which is absolute nonsense. Also my Ricoh GXR APS-C modules are sold as 28mm (actual 18.3mm) and 50mm (actual 33mm) ones and there are many others as well. Therefore the source is undoubtfully the camera industry itself.


I don't recall anything like "equivalences" until the 1970s. Camera manufacturers and users were all talking about real focal length. The Hasselblad was sold with a 80mm Planar and the Minox with a 15mm Complan lens. When Pentax launched its first SLR for 110 miniature format, the lenses were all labelled under their real focal length but Pentax nevertheless did mention the "35mm equivalent focal length" of the lenses on its advertising material, like for example in this 1979 ad:



I don't know whether Pentax was the first to use this notion of "equivalence", but it would seem logical that marketing departments at that time would think of something to help promote the "system" miniature cameras that were beginning to appear then: Pentax 110, Minolta 110 zoom and later, Canon EOS IX, Minolta Vectis and Nikon Pronea.

Cheers!

Abbazz


PostPosted: Mon Jan 15, 2018 11:38 pm    Post subject: Reply with quote
Abbazz wrote:
I don't recall anything like "equivalences" until the 1970s. Camera manufacturers and users were all talking about real focal length. The Hasselblad was sold with a 80mm Planar and the Minox with a 15mm Complan lens. When Pentax launched its first SLR for 110 miniature format, the lenses were all labelled under their real focal length but Pentax nevertheless did mention the "35mm equivalent focal length" of the lenses on its advertising material, like for example in this 1979 ad:...

I don't know whether Pentax was the first to use this notion of "equivalence", but it would seem logical that marketing departments at that time would think of something to help promote the "system" miniature cameras that were beginning to appear then: Pentax 110, Minolta 110 zoom and later, Canon EOS IX, Minolta Vectis and Nikon Pronea.



"System 10 comes with a standard Pentax 24mm f2.8 lens. It has 6 elements in 5 groups and it's the equivalent of a normal 50mm lens in the 35mm format"

Well, I didn't expect that Abbazz. The buggers were using 'equivalence' in the film era. Nice find. Funnily enough, I recognised that advert, so I'm guessing I pored over it in my youth.


You could suspect Pentax as being the original culprit when you consider that their 110 was an SLR, so it must have been tempting to find a way of promoting it to 35mm SLR users of the time. But that's guessing. The advert is dated 1979, so we have a marker. This is getting interesting. Time to check a few adverts from the 1970s.

Cheers man.


PostPosted: Tue Jan 16, 2018 12:20 am    Post subject: Reply with quote
Gatorengineer64 wrote:
There is a ton of mis-information, but a MF lens shoots roughly life a ff lens three stops faster only FROM a depth of field standpoint. It will still shoot from an exposure standpoint like its native, but for isolating a subject that is where the strength of medium format on FF is. Also I cant think of a 250 F3.5 on Full frame that can be had for the price of a kiev 88 MF lens. you can google it or use F calc.

http://fcalc.net/


On MF camera, yes, compared to on FF.

MF lens dof on MF camera is same as FF lens of 1/2 focal length and 2x faster aperture on FF.

Not the other way around.

The MF 250/3.5 lens on FF will give same dof as FF 250/3.5 lens on FF.

The larger format gets the narrower dof, compared to smaller format, not the other way around.


PostPosted: Tue Jan 16, 2018 1:22 am    Post subject: Reply with quote
I don't really understand why the industry went with the "equivalent" system instead of using angle of view but there it is. Mass confusion. I have used my P67 lenses to good effect on full frame, or even APS-C though I don't recall testing the 105mm 2.4....

I bump my "lichen wine" shot every time I get a chance, here is my 55mm f4 on Canon 60D:

http://forum.mflenses.com/pentax-67-55mm-f4-on-canon-60d-with-macro-tubes-t73530.html


PostPosted: Tue Jan 16, 2018 1:42 am    Post subject: Thank You Blotafton Reply with quote
Thank you Blotafton, Your link proves my point about Depth of Focus of MF versus FF. Its a shame that nearly no one here would take the time to click on it, and that they would rather continue in their mis-understanding. The Medium format is a much nicer image (perhaps its a better lens) than the FF, but the blurs are almost equivalent at 2 stops slower for the FF. Relative to the question about the Pentax 105, I will pick one up when a well priced opportunity arises and post my results here. For the record the comment was about depth of focus, not viewing angle or speed equivalence. I do understand all factors other then depth of focus are independent of sensor or film size.


PostPosted: Tue Jan 16, 2018 10:29 am    Post subject: Re: Thank You Blotafton Reply with quote
Gatorengineer64 wrote:
Thank you Blotafton, Your link proves my point about Depth of Focus of MF versus FF. Its a shame that nearly no one here would take the time to click on it,...

For the record the comment was about depth of focus, not viewing angle or speed equivalence. I do understand all factors other then depth of focus are independent of sensor or film size.


I can commend the photographer in Blotafton's link for making the effort and sharing. I for one, certainly looked at it. But in terms of providing a depth of field comparison, it's not a good comparitive test. You really need to take a shot of something with graduation marks in order to judge, like a ruler. But it would be wrong to blame the photographer for this. He uses the title "Faking it", and says in the link he set off to emulate a medium format lens, including using post-processing (cropping) to do this. He was never doing a straight comparison.

On the subject of "all factors other than depth of focus are independent of sensor or film size", my understanding is this -

Depth of focus (field) is dependent on the distance from the subject, not the sensor or film size.

When using the same lens on different sensor or film size cameras, the depth of focus available remains the same. What can change is the distance from the subject in order to create the same image. If a photographer uses say a lens on a full frame camera, then swaps the same lens to a smaller sensor, he will have to stand further away to get the same shot. Being further away increases the depth of focus. You can check this on any lens with a depth of field scale.

When using the same lens on differing sensor sizes, the only thing that is dependent on the sensor size, is field of view.

I hope you don't take this as a wind up Gatorengineer64.


PostPosted: Tue Jan 16, 2018 1:55 pm    Post subject: Reply with quote
Nice clear explanation Sciolist, thank you!

I think by cropped he means crop the width to same length as height, no resizing, he only chopped off the sides to get another square for comparing.



Fwiw I have tried 6x7 105/2.4 on FF! Years ago, I can't find the examples yet. Iirc, it did seem to perform as well as M42 S-M-C Takumar 105/2.8, except for the size and weight. Both lenses are long gone....


PostPosted: Tue Jan 16, 2018 3:19 pm    Post subject: Reply with quote
visualopsins wrote:
Nice clear explanation Sciolist, thank you!

I think by cropped he means crop the width to same length as height, no resizing, he only chopped off the sides to get another square for comparing.



Fwiw I have tried 6x7 105/2.4 on FF! Years ago, I can't find the examples yet. Iirc, it did seem to perform as well as M42 S-M-C Takumar 105/2.8, except for the size and weight. Both lenses are long gone....


The main problem with the example linked to is that it shows an image taken using a medium format camera with a medium format lens, and compares it to an image using a full frame camera with a full frame lens. Gatorengineer64 is asking for comment on a full frame camera with a medium format lens.

Gatorengineer64 mentioned his choice might be good for portraits. I think my original comment was that it could make a fine one, but due to having to stand further away from the subject with a full frame sensored camera, the depth of field would increase for any given aperture on the medium format lens. I pointed this out as I know a narrow depth of field is helpful in achieving a good traditional portrait. It was a 'heads up', more than anything.


PostPosted: Tue Jan 16, 2018 5:41 pm    Post subject: Reply with quote
Ah, and therin lies the confusion!

Gatorengineer64 doesn't have a 6x7 camera!

He was simply asking, since 105/2.8 on FF makes a great portrait lens, shouldn't 6x7 105/2.4 make a good portrait lens on FF too? Also it's 0.4 stops faster. And he's going to stand in the same spot, not move back!


PostPosted: Wed Jan 17, 2018 3:54 am    Post subject: Re: Anyone try a Pentax 67 105f2.4 on any fullframe DSLR? Reply with quote
Gatorengineer64 wrote:
Im loving my Jupiter 36B 250 F3.5 on my A7R2...the shallow depth of field and its corner to corner sharpness are very nice. It has a little CA but correctable in post processing. It also serves as a great personal defense weapon, as well as a portable gym. will be a blast to shoot at my sons soccer games next year...

Given the outstanding reputation of the Pentax 67 105F2.4, has anyone shot it on full frame? I believe it might be an unbelievable portrait lens for under $300 with adapter. (its DOF is the equivalent of a 1.2ish native. my go to portrait now is a zeiss 85 2.8 planar.

Thoughts?


Yes, i think it would give still 105mm fov but 1.2 speed. There is a blog showing this with a Flektogon 4/50 for Praktica 6 but used on a 5D. The FL stays the same. I assumed the shutter speeds if used Av mode would be faster though, effectively doubled. I think this is the case.


PostPosted: Wed Jan 17, 2018 4:39 am    Post subject: Re: Anyone try a Pentax 67 105f2.4 on any fullframe DSLR? Reply with quote
crouu wrote:
Gatorengineer64 wrote:
Im loving my Jupiter 36B 250 F3.5 on my A7R2...the shallow depth of field and its corner to corner sharpness are very nice. It has a little CA but correctable in post processing. It also serves as a great personal defense weapon, as well as a portable gym. will be a blast to shoot at my sons soccer games next year...

Given the outstanding reputation of the Pentax 67 105F2.4, has anyone shot it on full frame? I believe it might be an unbelievable portrait lens for under $300 with adapter. (its DOF is the equivalent of a 1.2ish native. my go to portrait now is a zeiss 85 2.8 planar.

Thoughts?


Yes, i think it would give still 105mm fov but 1.2 speed. There is a blog showing this with a Flektogon 4/50 for Praktica 6 but used on a 5D. The FL stays the same. I assumed the shutter speeds if used Av mode would be faster though, effectively doubled. I think this is the case.


Can you share the link to the blog post, please? Unfortunately lens speed will be f2.4. Flectogon 4/50 for Practica 6 on 5d same, f4 in that case. A great example earlier in this thread, imagine an evenly lighted circle projected on paper as what the large format lens projects onto the large film in the Practica. Now toss a smaller piece of paper, representing the 5d sensor into the circle. Light shining on that smaller paper is no brighter than the surrounding light, yes?


PostPosted: Wed Jan 17, 2018 2:11 pm    Post subject: Reply with quote
I'm summarizing here the (wrong) statements of "Gatorengineer64" concerning the depth of field of medium format lenses on Full Frame cameras.
He (wrongly) states that a medium format Pentax 2.4/105mm lens has a much shallower depth of field than (for instance) a FF lens such as the Nikkor 2.5/105mm. He even goes as far as telling that the medium format lens has "2-3 stops" shallower depth-of-field, compared to the 2.4/105mm FF lens:

Gatorengineer64 wrote:

Given the outstanding reputation of the Pentax 67 105F2.4, has anyone shot it on full frame? I believe it might be an unbelievable portrait lens for under $300 with adapter. (its DOF is the equivalent of a 1.2ish native.)
Thoughts?


Gatorengineer64 wrote:
There is a ton of mis-information, but a MF lens shoots roughly like a ff lens three stops faster only FROM a depth of field standpoint. It will still shoot from an exposure standpoint like its native, but for isolating a subject that is where the strength of medium format on FF is.


Gatorengineer64 wrote:
You are of course completely right, except when it comes to DOF.... You cant "crop" out depth of field, its not a function of the distance from the center of frame. We agree that a MF has a deeper Depth of field, now when you only take part of that frame, you are still taking the whole DOF with it. if that makes sense. ... Its also readily googleable.


Gatorengineer64 wrote:
"We agree that a MF has a deeper Depth of field,"

Yes I got this backwards, (at the time greater in my pea sized brain meant better for portraits, but yes, I had it backwards, and it made me sound like an idiot).

I stand by what I say and what I have read, you cant crop depth of field and a MF lens has a shallower Depth of field than a FF, because it is illuminating a larger sensor (film being a sensor). ... the DOF does change. Part of the medium format look is that shallower DOF.

Im hoping some here that have the gear can post some examples.


Gatorengineer64 wrote:
Your link proves my point about Depth of Focus of MF versus FF. Its a shame that nearly no one here would take the time to click on it, and that they would rather continue in their mis-understanding. The Medium format is a much nicer image (perhaps its a better lens) than the FF, but the blurs are almost equivalent at 2 stops slower for the FF.


And here comes reality.
Mamyia 2.8/80mm lens (medium format) compared to Minolta 1.4/85mm (Full Frame), both lenses used on 24MP FF DSLR.
According to "Gatorengineer64" the Mamiya @ f2.8 should be equivalent to the Minolta @f1.4. It isn't.


Stephan


PostPosted: Wed Jan 17, 2018 2:23 pm    Post subject: Reply with quote
And here, the same images as above, again, but re-arranged according to my previous statements:



In fact, the full frame Minolta lens - compared at the same aperture - has even the better background blur than the medium format Mamiya! Why?

1) the Minolta has slightly longer focal length => slightly less depth-of-filed (=more background blur) if focusing distance and f-stop are identical
2) the Minolta was deliberately engineered as a portrait lens, thus emphasizig bokeh (ahich is not the same as the more general term of "background blur"!).

I hope this clear images will end the discussion.

Stephan


PostPosted: Wed Jan 17, 2018 5:43 pm    Post subject: Reply with quote
stevemark wrote:
And here, the same images as above, again, but re-arranged according to my previous statements:



Stephan


Thank you, this should settel it.


PostPosted: Wed Jan 17, 2018 7:36 pm    Post subject: Reply with quote
Good work Stephan.

I should do a similar compare, I have a Noritar 80/2 made for the Norita/Graflex 6x6 SLR (very similar to the Pentax 67).
Its already set up on an M42 mount.

http://forum.mflenses.com/norita-noritar-80-2-mf-lens-repaired-and-adapted-t13437,highlight,%2Bnorita.html

I should do another portfolio on this one. Its a bit of a wreck but the glass is fine.

I could check it against my 85mm Nikkor or 75mm Biotar perhaps .


PostPosted: Wed Jan 17, 2018 10:34 pm    Post subject: Reply with quote
stevemark wrote:
I hope this clear images will end the discussion.
Stephan


Thank you, Stephan. Very well done!

This shows exactly why the Minolta AF 85/1.4 is one of my most favorite lenses. Wink


PostPosted: Wed Jan 17, 2018 10:40 pm    Post subject: Reply with quote
Bravo! There's no medium format camera there!

To complete the set of examples we need to see that Mamiya len's results from Medium Format camera, shown side by side with results of 35/1.4 lens on FF camera. Smile.

A complete set of examples answers all of the questions, yes?

EDIT: Also needed is a third comparison of Mamiya on medium format camera side by side with same Mamiya lens on FF where FF camera is moved farther away to obtain the same framing. All the other examples are made with camera(s) the same distance from subject. This new set shows what happens when the framing rather than distance is kept constant.


PostPosted: Thu Jan 18, 2018 9:23 am    Post subject: Reply with quote
Nice work Stephen. Thanks for doing that.


PostPosted: Fri Jan 19, 2018 6:45 pm    Post subject: Reply with quote
#1


Left: S-M-C Takumar 6x7 (MediumFormat) 105/2.4@2.8
Middle: S-M-C Takumar 6x7 (MediumFormat) 105/2.4@2.4
Right: Auto-Takumar (FullFrame) 105/2.8@2.8

Focus chart at ~45degrees and ~5ft away
Camera is Canon 6D

My assessment is that DOF is same at same fstop.

John


PostPosted: Sat Jan 20, 2018 12:03 am    Post subject: Reply with quote
Nice test! Like 1


PostPosted: Sun Jan 21, 2018 2:56 pm    Post subject: Reply with quote
visualopsins wrote:
Bravo! There's no medium format camera there!

To complete the set of examples we need to see that Mamiya len's results from Medium Format camera, shown side by side with results of 35/1.4 lens on FF camera. Smile.

A complete set of examples answers all of the questions, yes?

EDIT: Also needed is a third comparison of Mamiya on medium format camera side by side with same Mamiya lens on FF where FF camera is moved farther away to obtain the same framing. All the other examples are made with camera(s) the same distance from subject. This new set shows what happens when the framing rather than distance is kept constant.


Being a scientist myself, i know it's never a good idea to run experiments/tests and changing several parameters at the same time. Lots of confusion will be gereated, when you change lens, sensor (film) size, aperture, focal length, and finally the size of the print at the same time...

Stephan


PostPosted: Sun Jan 21, 2018 3:35 pm    Post subject: Reply with quote
stevemark wrote:
visualopsins wrote:
Bravo! There's no medium format camera there!

To complete the set of examples we need to see that Mamiya len's results from Medium Format camera, shown side by side with results of 35/1.4 lens on FF camera. Smile.

A complete set of examples answers all of the questions, yes?

EDIT: Also needed is a third comparison of Mamiya on medium format camera side by side with same Mamiya lens on FF where FF camera is moved farther away to obtain the same framing. All the other examples are made with camera(s) the same distance from subject. This new set shows what happens when the framing rather than distance is kept constant.


Being a scientist myself, i know it's never a good idea to run experiments/tests and changing several parameters at the same time. Lots of confusion will be gereated, when you change lens, sensor (film) size, aperture, focal length, and finally the size of the print at the same time...

Stephan


I think having the additional examples would clear up lots of confusion people have. I agree perhaps you are right the additional examples would also generate lots of confusion for people who don't understand what is being shown. The additional examples are meant to compare not change parameters.


PostPosted: Mon Jan 22, 2018 6:12 am    Post subject: Reply with quote
Ha ha! The principles I want examples for are now being included in lens reviews!

Quote:
Comparing it to a full frame lens on a full frame camera, in terms of perspective and depth of field with the same framing, the 7Artisans 35mm f/1.2 is equivalent to a 50mm lens (ish) field of view with a maximum aperture of around 1.8. Of course, whilst that’s a little less exciting if you’re used to shooting full frame cameras, it is a fairly unique specification when combined with the size and price of this lens. The wider aperture with slightly broader DOF than a fast lens on a full frame camera also narrows the gap in terms of the low light performance comparison with a bigger camera too.


https://www.35mmc.com/20/01/2018/7artisans-35mm-1-2-mini-super-sonnar/

Thanks to new member Lupus78 for the link.
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