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02-12-2009, 11:15 PM   #61
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I don't know about the Tamron. But a more valid comparisson would be between the FA 50 and the 67 55mm lenses - both being primes. I don't think a standard zoom (whether it be the Tammy, a Sigma or a Pentax or Canon etc.) can reach the peak MTF of a fixed focal length lens. Especially not, as they cover quite a wide reach from wide-angle to a light tele on APS-C.

On the other hand, you sure profit from the sweet spot behaviour of the 67 lens on the tiny digital sensor. Published lens data suggest, that resolution for larger formats goes down heavily, compared to 35mm. So you will find tele lenses for 4x5 or larger, that are considered to be solid performers with resolutions as low as 30 lp/mm and even less.

I think the point is, that MF and LF lenses do not need the high resolving power, but that does not prevent the lens designer to achieve high res with such a lens sometimes. Maybe the Pentax 55mm falls into this category?

Ben
Ben:

I appreciate all the information you provide here. I do not own the Fa 50, but here are 5 lenses, all @ f8, 1.6 seconds, with %100 crops for comparison. The lenses are: 1) Pentax Auto Takumar f 1.8 55mm 2) Pentax M 1.7 50mm 3) Pentax A 1.7 50mm 4) SMC Pentax 67 f4 55mm 5) SMC Takumar f 1.4 50mm.

I also shot them at f4 and f5.6. If any expresses an interest, I'll post the crops @ f4 or 5.6 as well. EXIF data purposively stripped:


Last edited by Jewelltrail; 11-29-2010 at 11:22 PM.
02-12-2009, 11:39 PM   #62
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I have heard this about the resolving power of medium format lenses but in real life that doesn't seem to be the case, at least to me. This is a A*300mm 645 lens on my DS and it seems to be very sharp to me. I don't have a 67 to K adapter, just a 67 to 645 adapter which puts the lens too far out when used together on a DSLR.



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02-13-2009, 02:38 AM   #63
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QuoteOriginally posted by Jewelltrail Quote
Ben:

I appreciate all the information you provide here. I do not own the Fa 50, but here are 5 lenses, all @ f8, 1.6 seconds, with %100 crops for comparison. The lenses are: 1) Pentax Auto Takumar f 1.8 55mm 2) Pentax M 1.7 50mm 3) Pentax A 1.7 50mm 4) SMC Pentax 67 f4 55mm 5) SMC Takumar f 1.4 50mm.

I also shot them at f4 and f5.6. If any expresses an interest, I'll post the crops @ f4 or 5.6 as well. EXIF data purposively stripped:
Thank you so much. That's an interesting series of images. For me the images No. 1 and 3 are slightly ahead of the others in terms of sharpenss/contrast. But all in all there are so many possible reasons for this (slight varianes in exposure, compresssion etc.), that it is hard to conclusively decide, which comes out best.

It is clear, that the 67 55mm lens delivers results on a comparable level to the 35mm lenses - very nice.

Ben
02-13-2009, 11:51 AM   #64
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Thank you so much. That's an interesting series of images. For me the images No. 1 and 3 are slightly ahead of the others in terms of sharpenss/contrast. But all in all there are so many possible reasons for this (slight varianes in exposure, compresssion etc.), that it is hard to conclusively decide, which comes out best.

It is clear, that the 67 55mm lens delivers results on a comparable level to the 35mm lenses - very nice.

Ben
I agree with everythig you say. Would you like to know which images go with which lenses? Also, do you think the conclusion you reach after seeing these images would hold for other 67 Pentax lenses? If the 67 SMC 55mm f4 is on a par with these other Pentax primes, as we think it is, then would you agree that when large prints are sought the 67 55 f4 would be very desirable?

02-13-2009, 12:53 PM   #65
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QuoteOriginally posted by Jewelltrail Quote
I agree with everythig you say. Would you like to know which images go with which lenses? Also, do you think the conclusion you reach after seeing these images would hold for other 67 Pentax lenses? If the 67 SMC 55mm f4 is on a par with these other Pentax primes, as we think it is, then would you agree that when large prints are sought the 67 55 f4 would be very desirable?
I think, there is more to using 67 lenses, then "only" image quality. First and foremost - provided the IQ is on the same level, which your example basically demonstrates - I would usually buy a 35mm or APS-C lens, simply because they are smaller and faster. Add on top the simple convenience factor (A-setting, may be AF, at least auto-diaphragm with K- and M-lenses), which I personally don't find wholly negligible.

On the other hand, if you already have 67 lenses or you can get a special focal length, which would be much more costly for 35mm (the old 67 600/4 springs to my mind, though it shows heavy CA) at a very good price, then the 67 lens would be a viable option. But I personally would not buy commodity focal lengthes off the 67 line for use on a DSLR, due to the above mentioned issues. For me that translates into a simple equation: I personally would not buy any 67 lens under or up to 400mm focal length, only for use with a DSLR. Above that, it is a matter of price, availability etc.

One problem is, that you cannot expect all the 67 lenses to be of the same quality. There surely will be better and not quite so good lenses - as within any other lens portfolio. Pricewise the most interesting lenses are the really long focal lengthes, which are somehow much cheaper, than the 35mm equivalents (A or FA modells). But That is largely true only for the older modells, like the 600/4, I already mentioned. And these come wothout ED glass, which reduces CAs, which otherwise get more pronounced when the focal length increases. Also one needs to take into account (literally), that the longer 67 lenses are really big and heavy. If you read up experiences by photographers who really use these giants, you will also learn, that you have to invest another 1000 USD for a tripod and head, which is sufficient for such a beast.

In practice I have a couple of medium format lenses, for which I have adapters to use with my K-mount bodies - but indeed I never use them, as I have all the focal lengthes in the 35mm version, too.

Ben
02-13-2009, 02:04 PM   #66
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#1 is my favorite--it's the sharpest (I'm judging by looking at the dust specs just below the main "gem" or alternatively just beside it). #1 also seems to have the best contrast and color, but as Ben notes, it is also the one with the darkest exposure which I tend to prefer and which influences the perception of contrast.

#2, #3 and #5 are pretty equivalent for sharpness--again the dust test--the bigger the spot of dust appears the less sharp it is.

#4 has the softest focus by a rather wide margin--dust specs are double the size due to softening of the edges "smearing" them.

I'll hold a drum-roll waiting to find out which is the 67 lens. Hopefully, none were shot as JPEG's which have in-camera sharpening. Though I guess if the softness can be sharpened away, that would reduce the issue of resolution...

Like Ben, I have a kit of medium format and a kit of 35mm/digi stuff, so it isn't like a major issue to me. But it would be fun to cross-apply at times...

The 645 image appears sharp and the resolution of 645 glass is closer to the smaller format to begin with. It certainly seems acceptable. The image appears to be heavily sharpened in pp or is that just my prejudice knowing that the lens doesn't resolve anywhere near as sharp as the DA* or FA* 300's?

Regardless, having fun with optics is what this hobby is all about, so we should all knock ourselves out doing stuff we like to do, regardless of what a lens resolution chart says, or what a magazine article says, or some forum tramp posts, or ...
02-13-2009, 02:07 PM   #67
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Looking again, #5 is pretty sharp as well...perhaps rivals #1. But here I am posting while sober again. Bet they all look pretty similar through "affected" eyes!
02-14-2009, 01:39 AM   #68
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Ron Boggs:

#1 is my favorite--it's the sharpest (I'm judging by looking at the dust specs just below the main "gem" or alternatively just beside it). #1 also seems to have the best contrast and color, but as Ben notes, it is also the one with the darkest exposure which I tend to prefer and which influences the perception of contrast.

#2, #3 and #5 are pretty equivalent for sharpness--again the dust test--the bigger the spot of dust appears the less sharp it is.

#4 has the softest focus by a rather wide margin--dust specs are double the size due to softening of the edges "smearing" them.

I'll hold a drum-roll waiting to find out which is the 67 lens. Hopefully, none were shot as JPEG's which have in-camera sharpening. Though I guess if the softness can be sharpened away, that would reduce the issue of resolution...

Like Ben, I have a kit of medium format and a kit of 35mm/digi stuff, so it isn't like a major issue to me. But it would be fun to cross-apply at times...

The 645 image appears sharp and the resolution of 645 glass is closer to the smaller format to begin with. It certainly seems acceptable. The image appears to be heavily sharpened in pp or is that just my prejudice knowing that the lens doesn't resolve anywhere near as sharp as the DA* or FA* 300's?

Regardless, having fun with optics is what this hobby is all about, so we should all knock ourselves out doing stuff we like to do, regardless of what a lens resolution chart says, or what a magazine article says, or some forum tramp posts, or .
Are you any relation to Wade Boggs? Sorry, I'm a big Red Sox fan and remember watching him crush many a baseball.

Okay, first things first. All the shots were taken in PEF. There was no post-processing. I did my best to achieve maximum manual focus with my split prism, but may have missed on the 4th image. They were all cropped at 100 percent from their originals and I took a lot of care to minimize any variables. The only exception to this is number 4, which although at f8 and 1.6s like all the others, rendered a good deal brighter. So I did about a 10 percent reduction to exposure on the 4th shot--that is the only modification done to any of the images. And here are the lenses:

# 1 is the Super Takumar 50mm SMC f1.4
# 2 is the A 50mm f 1.7
# 3 is the M 50mm f 1.7
# 4 is the Auto Takumar 55mm f 1.8
# 5 is the SMC 67 55mm f4

Incidentally, and perhaps ironically, my copy of the Super Tak used here has that yellowish tint to the glass which may or may not have something to do with it having the darkest exposure, even though it used identical EXIF to the others.


Last edited by Jewelltrail; 02-14-2009 at 01:51 AM. Reason: add one more thing
02-14-2009, 09:57 AM   #69
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QuoteOriginally posted by Ben_Edict Quote
Brian, I ordered a back for my 4x5 from China and will see, how it works out. It would be a killer for studio work, but I can imaging using it for landscapes, too albeit perhaps not with the full 4x5 area. Two rows of four exposures seem to be doable to me, but experience will tell.

Ben

Ben, I would be very interested in hearing the results of your experiment after you have used the back on your 4x5.
02-14-2009, 10:14 AM   #70
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I have found some niche fits for my 67 glass. However, most of my serious shooting is landscape, which neither demands fast glass, nor lenses with automatic focus and apertures. I also enjoy the whole experience of manually focusing and stopping down a lens as well as using my own brain to optimize metering. But there are other things I like about the 67 glass on my K20.

Firstly, I have gotten some good deals on 67 glass. For example, I got the 6 x 7 165 f 2.8, in like new condition, for under $90. There are no 35mm counterparts to this option! Also, though I do not know why, the 67 glass seems easier to manually focus. The bokeh on the 67 glass is also better from what I have seen of the 3 lenses I own. I also find it easy to hand hold all three 67 lenses I own.

And as Ben says, the 67 glass may be an option to some people's tele needs. At this point, most of the 67 glass (especially the older stuff) does get heavy and hand holding is ruled out. Even still, it may fill this niche for some, particularly if the pricing stays down. The ED 67 for the 300 and the 400 is supposed to be simply stunning on 67 format--not sure how they would work on crop sensors, but would love to see some examples here.

Yes, I agree too with you Ben on the varying quality of 67 glass out on the market. Our forum is not yet rich enough in reviews to help all of us out here on lens quality. But this site Antique and Classic Cameras provides a decent introduction to the 67 lineup.

Finally, as you have seen, the image quality of at least some 67 lenses is excellent on DSLRs. In the test above I did on the Pentax 50mms, I need to note that the crops are taken from nearly the center. If anything, this setup favors the strengths of the 35mm lenses. Had I opted to crop from the edges, I have to believe the results would have made the 67 55mm look even better. And my initial work on the 67 200mm vs the Pentax M series 200m f4 looks like, again, the 67 glass is at least as good on the DSLR. And so far, though I must do the testing over, the 67 200mm looks a lot better than the 35mm 200.

As Ron says, it is all about having fun. To this end, I'll keep set my sails with this awesome hobby!

Best Regards,

Ernest

Last edited by Jewelltrail; 02-15-2009 at 11:23 AM. Reason: spelling
02-14-2009, 11:49 AM   #71
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Crop Factor 2.9

Yikes!! That means that the "Takumar SMC 300mm 4.0 Lens for Pentax 6x7 Camera" a on Ebay (~$220.00) would be "like" having an 870mm 4.0 lens. And the the SMC Pentax 67 6x7 SHIFT 75mm 4.5 Lens also on ebay would be a "tiltshift" 200mm currently bidding for $130.
Oh and the addid cost of an adaptor ring.....Too bad I just spent all my allowance on studio strobes.
02-14-2009, 12:27 PM   #72
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Careful, don't make the same mistake I made. The 75 shift lens is ONLY a shift lens. It doesn't have tilt. I bought one from KEH about 7 or 8 years ago and had to return it because I really wanted tilt, not shift. I believe the K mount 28mm shift is also a shift only lens.

Horseman makes a really nice tilt and shift bellows that can be adapted to K mount or 67 mount, but it doesn't allow for infinity focus and works as a bellows with movements for studio or close-up work.

To get tilt on my 67II's I bought a Zork Multi-Focus System with a Rodenstock 105 APO enlarger lens. The Zork unit has lots of tilt built-in and can have shift added for those so inclined. Now the really cool set-up may be to adapt the Zork for 67 to K mount for the new digi bodies. Maybe I'll do that someday, just not today!
02-14-2009, 12:43 PM   #73
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QuoteOriginally posted by ray94553 Quote
Yikes!! That means that the "Takumar SMC 300mm 4.0 Lens for Pentax 6x7 Camera" a on Ebay (~$220.00) would be "like" having an 870mm 4.0 lens. And the the SMC Pentax 67 6x7 SHIFT 75mm 4.5 Lens also on ebay would be a "tiltshift" 200mm currently bidding for $130.
Oh and the addid cost of an adaptor ring.....Too bad I just spent all my allowance on studio strobes.
I cannot follow your calculations...

The 300mm Takumar would behave like a 300mm DA* lens in terms of image angle. It would be an equivalent angle to a 450mm lens on a 35mm film or FF camera.

The 75mm Shift is a 75mm lens on the DSLR, a moderate tele photo. In terms of image angle this is equivalent to a 125mm lens on a 35mm or FF camera. Also I find it hard to imagine any sensible application for the shift function with such a long lens on APS-C. That would be different with a shift/tilt lens, which would find applications for table top photography, but this lens has no tilt.

Ben
02-14-2009, 12:57 PM   #74
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Ray94553: Crop Factor 2.9
Yikes!! That means that the "Takumar SMC 300mm 4.0 Lens for Pentax 6x7 Camera" a on Ebay (~$220.00) would be "like" having an 870mm 4.0 lens. And the the SMC Pentax 67 6x7 SHIFT 75mm 4.5 Lens also on ebay would be a "tiltshift" 200mm currently bidding for $130.
Oh and the addid cost of an adaptor ring.....Too bad I just spent all my allowance on studio strobes.
Ray: If you go to the start of this thread you will get a decent explanation of focal length, as affected by crop sensors, 35mm and Medium Format.

Last edited by Jewelltrail; 02-15-2009 at 11:21 AM. Reason: clarity
02-16-2009, 01:32 PM   #75
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For all those worried about my interpretation of crop factor. I've been corrected on this many times. But I think my way of saying is just fine
It just seems obvious to me that the focal length remains the same but the field of view covered is varied by the "Crop Factor". Notice that I said; "LIKE" having an 870mm 4.0 lens. This is because the field of view is cropped to a view presented is similar to that of an 870mm lens at that same lens to subject distance, while angle of view and the aperture (DOF) remains the same. Also another possible advantage gained is that you’re using the center of the lens and therefore you may see less edge distortion depending on the lens.. I stated things this way so as not to confuse anyone into thinking that the image is actually cropped.
If I take a 10 megapixel image and crop it by a factor of 0.5, I have lost half the data and half the pixels. The image is smaller it is no longer a 10 megapixel image and it can only be printed at half the size of the original. On the other hand an image, created by a lens and camera body combination that has a crop factor of 2, that 10 megapixel image will have half the area of view of a lens of the same focal length with a crop factor of 1. However, in order to “zoom in” without loosing data and pixels, and staying with a 35mm lens on a 35mm camera body, you would need a lens with the longer focal length.
While a 6x7 300mm lens mounted on a 2/3 sensor digital camera body may not produce an exact 870mm focal length image, for the money it’s a darn close cousin.
If anyone can find a better shorthand way of describing this relatively simple rule of optics please tell me.

As for the tilt lens, while I have never used a tilt only lens on a camera I have used the tilt shift on a 4x5 field camera many years ago. So while it may be out of my budget presently, the thought of experimenting with it for those few dollars does look inviting.
Years ago I picked up a reversing ring for my 50mm f1.4 just to play with it as a macro. Flipping tings around on the fly wasn’t all that easy, but back then, “on the fly” wasn’t always that fast or easy. The 50mm got trashed when it fell up in the Sierras, and the ring went in some trade. These days for macro work I don’t experiment anymore, I use a Vivitar Series I 105mm lens. It has a great bokeh, and is built like a tank. But a long lens tilt, I do wonder what that would be like.
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