[Jewelltrail]

Baldeagle21b: Success! It took a little lubrication on the lens flange and a little more effort than I anticipated at first, but it works and the lens locks on to the adapter. Thanks to all for the suggestions.

Yesssssssssssssss--ain't success sweet, especially when snatched from the jaws of defeat? Good for you! Now post some shots--Pleeeeeeeeeeeeze.

[HarryN]

Hi - sorry for being dense, but after reading it all, I just want to double check. Using the 0.5 effect noted in Ole's post (# 6)

Example lens 6 x 7 format, 200mm, F4 lens, mounted on a 35mm ME Super.

With a conventional M type 200mm F4 lens, it would behave with manual focus, aperature priority auto exposure and auto stop down.

With the 6x7 lens, it would behave like a nominal 400mm, F4 lens, manual focus.

I am unclear yet if it would work with the aperature priority and auto stop down aspect. I guess I need to learn more about 6x7 lenses.

[feverbeaver]

Hi - sorry for being dense, but after reading it all, I just want to double check. Using the 0.5 effect noted in Ole's post (# 6)

Example lens 6 x 7 format, 200mm, F4 lens, mounted on a 35mm ME Super.

With a conventional M type 200mm F4 lens, it would behave with manual focus, aperature priority auto exposure and auto stop down.

With the 6x7 lens, it would behave like a nominal 400mm, F4 lens, manual focus.

I am unclear yet if it would work with the aperature priority and auto stop down aspect. I guess I need to learn more about 6x7 lenses.

The field of view is the same for 200mm 4.0 M type or 6x7 on a dSLR. It is like a 300mm 4.0 on a film-SLR (like the LX).

The use of a 6x7 on a dSLR is like the use of a preset-lens. Manual fokus and then stop down. You can use the Av-mode.

[calicojack]

The use of a 6x7 on a dSLR is like the use of a preset-lens. Manual fokus and then stop down. You can use the Av-mode.

I umderstand this with the 6X7 or 67 lenses. Is this also true for the 645 lenses? I assume it is for the earlier ones but how about the later 645 "A" lenses? I guess there would need to be a 645A to KA converter. Was that ever made?
Brian

[nanok]

i noticed there is a typical misconception about the quality of larger format optics on smaller format cameras. it seems to come from a sort of reverse-thinking: the format is larger, thus one needs to enlarge less to get the same results, compared to the smaller format. that sounds reasonable enough, only, that says nothing about the lenses, it says more about most of us' perception of larger formats .

as it was very clearly shown by our fellow pentaxian here, there is no significant difference in sharpness/resolving power, at least at first glance (the subject matter was not the most fortunate, i admit ), so here's a thought which might help wrap our minds around the concept:

film is generally about as good "per square cm", if it comes in 120 rolls or 35mm, and people who go to the hassle of buying, using, and suplying mf (or larger format) equipment, usually expect to get more out of it too, most people who shoot mf will _demand_ stunningly better quality, enlarging ability and so on than they can get from 35mm film equivalent solutions, because that's why they're in the game to begin with. this is perhaps why mf lens designers will still make the lenses as good as they can, actually, i have a hunch no lens designer ever had a lpm limit to design by (especially in those times), i remember clearly some lenses waited for quite a while untill film managed to catch up with them, and people actually managed to test them to the limit . i think, maybe, they just designed the lenses the best they could (and in some cases, as most of us know... damn, they were good..), and probably built them the best way possible while keeping the price within decent limits, and that was about it (many times, it seems to me, the difference in price was mostly from mechanical craftmanship and built quality, rather than optics)

i have recently gotten an adapter to give my old 80/2.8 biometar a new life, ofcourse it performs very nicely on the k20d (though, to be very honest, apart from the /2.8, the 70-150/4 smc-m has grown on me so much i can hardly justify using the biometar, maybe wide open, for portraits? i'll have to see..)

[Jewelltrail]

Nanok: as it was very clearly shown by our fellow pentaxian here, there is no significant difference in sharpness/resolving power, at least at first glance (the subject matter was not the most fortunate, i admit ), so here's a thought which might help wrap our minds around the concept

Yes, I agree, but I plan to do more testing in the near future. In the meantime, I hope to see some more interesting images from others.

There are things which did not show in the shots I posted here, but which are noteworthy. Firstly, I have only shot the MF lenses indoors, under controlled lighting--that is to be expected in a test like this. However, even from this limited shooting, it is clear to me the bokehs of the 3 MF lenses are extra nice, particularly those on my close focus SMC 67 200mm f4 & on my SMC 67 55mm f4: they focus @ 1.5 & 1/3rd of a meter, respectively.

Also, there appears to be thinner DOF from my testing, which produces cool 3D-like effects in shots. Although my initial post here was boring, and perhaps lead many to conclude there is no appreciative advantage from shooting MF on crop sensors, I honestly believe the lenses will produce uniquely beautiful images in real life landscape. I believe they will have their own indelible stamp imprinted onto their images.

[Jewelltrail]

Nanok: i noticed there is a typical misconception about the quality of larger format optics on smaller format cameras.

Can you point to this misconception as it exists here, in this thread? Or are you referring to a misconception which originates and is harbored outside of this thread? Thanks.

[Ben_Edict]

i noticed there is a typical misconception about the quality of larger format optics on smaller format cameras. it seems to come from a sort of reverse-thinking: the format is larger, thus one needs to enlarge less to get the same results, compared to the smaller format. that sounds reasonable enough, only, that says nothing about the lenses, it says more about most of us' perception of larger formats .

as it was very clearly shown by our fellow pentaxian here, there is no significant difference in sharpness/resolving power, at least at first glance (the subject matter was not the most fortunate, i admit ), so here's a thought which might help wrap our minds around the concept:

film is generally about as good "per square cm", if it comes in 120 rolls or 35mm, and people who go to the hassle of buying, using, and suplying mf (or larger format) equipment, usually expect to get more out of it too, most people who shoot mf will _demand_ stunningly better quality, enlarging ability and so on than they can get from 35mm film equivalent solutions, because that's why they're in the game to begin with. this is perhaps why mf lens designers will still make the lenses as good as they can, actually, i have a hunch no lens designer ever had a lpm limit to design by (especially in those times), i remember clearly some lenses waited for quite a while untill film managed to catch up with them, and people actually managed to test them to the limit . i think, maybe, they just designed the lenses the best they could (and in some cases, as most of us know... damn, they were good..), and probably built them the best way possible while keeping the price within decent limits, and that was about it (many times, it seems to me, the difference in price was mostly from mechanical craftmanship and built quality, rather than optics)

i have recently gotten an adapter to give my old 80/2.8 biometar a new life, ofcourse it performs very nicely on the k20d (though, to be very honest, apart from the /2.8, the 70-150/4 smc-m has grown on me so much i can hardly justify using the biometar, maybe wide open, for portraits? i'll have to see..)

Firstly, I think, all thread contributors acknowledged, that the particular lens, Jewelltrail tested against the 35mm lenses performed on the same level, resolution-wise. So I cannot see a general misconception.

Secondly: The advantage of larger film formats is not about higher resolution as such. It never was and you won't find that as being a decisive advantage in the literature as well. The decisive point of using larger film formats is about tonality and finer tonal differentation! This is, why you can recognize a quality difference between a print made from 35mm and 4x5 inch. This is basically the same difference you get between a APS-C DSLR and a medium format DSLR.

The highest resolution large format lenses achieve today, are defined by the Schneider-Kreuznach Apo Digitar series, as these are optimized for digital backs. Even these reach a resolution (offcially published by Schneider-Kreuznach) of a "mere" 60 lp/mm!

Going back to Jewelltrail's test. He used Pentax lenses, which seem to be acknowledged to be leading in terms of sharpness, contrast and resolution. I have none (except the old 500/4.5, which was available with 35mm or 67 mount and is not a good example in terms of contrast...), so I cannot validate that from my own experience. Photographers trying Mamiya lenses on the DSLR are generally disappointed (though this varies with the particualr lens used), as I read from several forum threads in dedicated pro forums. I will try that myself, if I find the time, as I have a nice collection of Mamiya glass, just need an adapter for K-mount.

So, I stand by my initial response, that in general lenses made for MF and LF sport a lower resolution/resolving power, than dedicated 35mm lenses. This is emphasized by the generally agreed circle of (least) confusion, which for 35mm is 0.025mm, whereas for 5x7 inch it is 0.145mm (nearly 6 times bigger in diameter) - and all intermediate formats lying within that range.

Anyway, we are discussing in this thread the general rule compared to particular practical experience. This is helpful and we can all derive new ideas from that. But single experiences do not devalidate a general rule.

Ben

[nanok]

Firstly, I think, all thread contributors acknowledged, that the particular lens, Jewelltrail tested against the 35mm lenses performed on the same level, resolution-wise. So I cannot see a general misconception.

okay, maybe i was a bit too vocal about it . i was talking about my general experience regarding discussions on the subject, not about this thread. actually, the reason i engage in such discussions at all here is that i notice there are people who have insight and _think_, which makes it very interesting and gives us all a chance to learn and have a broader view.

Secondly: The advantage of larger film formats is not about higher resolution as such. It never was and you won't find that as being a decisive advantage in the literature as well. The decisive point of using larger film formats is about tonality and finer tonal differentation! This is, why you can recognize a quality difference between a print made from 35mm and 4x5 inch. This is basically the same difference you get between a APS-C DSLR and a medium format DSLR.

that is a very interesting point, definetly worth noting. my mistake in giving the impression larger formats are _all_ about resolution/fine detail. another point often mentioned is the color "resolution" (which is closely connected to finer gradation you mentioned above), is that still meaningful with digital sensors though (does size still matter, if you have the same senzor? i think it does, indirectly, at least, because of dynamic range; any thoughts on that?)

The highest resolution large format lenses achieve today, are defined by the Schneider-Kreuznach Apo Digitar series, as these are optimized for digital backs. Even these reach a resolution (offcially published by Schneider-Kreuznach) of a "mere" 60 lp/mm!

Going back to Jewelltrail's test. He used Pentax lenses, which seem to be acknowledged to be leading in terms of sharpness, contrast and resolution. I have none (except the old 500/4.5, which was available with 35mm or 67 mount and is not a good example in terms of contrast...), so I cannot validate that from my own experience. Photographers trying Mamiya lenses on the DSLR are generally disappointed (though this varies with the particualr lens used), as I read from several forum threads in dedicated pro forums. I will try that myself, if I find the time, as I have a nice collection of Mamiya glass, just need an adapter for K-mount.

interesting point again, however in my case it is a biometar (which is pretty much the cheapest mf lens you can find around, for the cheapest mf system (arguably) that ever existed: pentacon six.

my initial tests indicate very decent performance with the k20d (14mp sensor, so quite dense). it is hard to decide, because these were not scientific tests, but shot in the real world, and it's hard to be sure critical focus was achieved, and so on. i was not unhappy with the results though (not blown away eyther, as i noted)

So, I stand by my initial response, that in general lenses made for MF and LF sport a lower resolution/resolving power, than dedicated 35mm lenses. This is emphasized by the generally agreed circle of (least) confusion, which for 35mm is 0.025mm, whereas for 5x7 inch it is 0.145mm (nearly 6 times bigger in diameter) - and all intermediate formats lying within that range.

Any way, we are discussing in this thread the general rule compared to particular practical experience. This is helpful and we can all derive new ideas from that. But single experiences do not devalidate a general rule.

Ben

correct, practical experience is different (but important imho). let me clarify what i was trying to say: not that the theory is wrong and we should ignore it, but that theory might not be always correct/complete, and that practical experimentation is worth it; at the end of the day, what you get from the lens is more important than what the numbers say, if you like the results and it delivers something you can't get easily otherwise, i think it is not important anymore if the numbers are "bad" in general (and, as you mentioned, might not be that bad for the particular lens). and i do agree that i would hardly buy a mf lens specifically for use on aps-c/35mm, unless i had a very specific need not covered otherwise (example: i bought recently a 300mm/4, again pentacon six system origin, it is big and heavy, but considered one of the best tele lenses one can buy, optically, and the price tends to be ridiculous. i cannot understate how big it is for a "mere" 300mm, though )

sorry for the confusion. i will try to find time for more careful tests with the humble biometar, and maybe also post some 100% crops and such.

thanks for the insight

[Ben_Edict]

nanok, I am very interested in your tests of the Pentacon/Practika lenses. I have the 300/4 myself and I recently comared the 500/5.6 against my Pentax K 500/4.5 and it stood up very well. Indeed I found the contrast to be on a somewhat higher level, but ofcourse I compared both lenses only fully open and then the Pentacon has 1/2 f-stop advantage.

I also have the old 180/2.8, which I never used on digital, because it really is big and heavy, even the M645 is dwarfed by it. But perhaps I should give it a try and compare it to my much more modern Sigma 70-200/2.8.

Ben

[HarryN]

Hi, I couldn't help but notice that in post 10, Jewelltrail's setup has the lens "right side up", but in post 30, feverbeaver's setup, the lens is "upsidedown".

I am hoping to use a lens "right side up" - is this a difference of adapters or something else ?

Thanks

HarryN

[Jewelltrail]

HarryN
Hi, I couldn't help but notice that in post 10, Jewelltrail's setup has the lens "right side up", but in post 30, feverbeaver's setup, the lens is "upsidedown".

I am hoping to use a lens "right side up" - is this a difference of adapters or something else ?

Thanks

HarryN

Hi Harry: See post # 18 to purchase an adapter where I got mine. Click on that link and you will also find pics and information about the adapter.

Feverbeaver made his own adapter, to his own specifications--he may have a specific need for the lens to be oriented this way. Let me know if you have any more questions. Best!

[feverbeaver]

Feverbeaver made his own adapter, to his own specifications--he may have a specific need for the lens to be oriented this way.

I turned the lens, so the Auto-Man-switch is on the left side. Now I can use this switch to focus on open aperture and close the aperture down to the preset value with one short move.

I also own the original Pentax adapter. This one have a little screw to lock the lens in 90° turns (for easier use of a lens with tripod mount).

[HarryN]

Hi - Thank you both for that information. I did follow the E Bay link and also saw the home-made adapter, but missed that this was on purpose.

Thank you for the clarification.

[Jewelltrail]

Nothing fancy, but finally got something outdoors with the close-focusing 200mm 67 lens on the k20: Shot f8--little crop