Edge failure on the 28mm F/3.5 M42 mount

Alden · 02-20-2018, 06:38 PM

I picked up a K-5IIs just for the purpose of trying legacy lenses, and read that many people praised the Takumar 28mm f/3.5. I found one in mint condition but was unimpressed by the coverage shot at f/11. While the center is excellent the edges fall away too much to be a usable lens for my taste. I also have the 35mm and it is sharp across the frame. So I was just wondering if I have a bad copy of this 28mm, or are others more forgiving? Can you look at yours at 100% and be satisfied with the sharpness to the sides?

stevebrot · 02-20-2018, 07:27 PM

Welcome to the Pentax Forums!

Which version do you have? Version 1 (1962-1966) has a 58mm filter ring and . Version 2 (1966-1971) has a 49mm filter ring. The two differ in optical design and physical size (Version 2 is smaller).

Steve

johnyates · 02-20-2018, 09:44 PM

Originally posted by Alden

While the center is excellent the edges fall away too much to be a usable lens for my taste.

That is my experience with this lens as well.

RAART · 02-20-2018, 10:38 PM

I do have Version 1 and I do not see so much fall off at the edges... Cannot find pictures now but this one shows at least some leafs on the edge... go on flickr to see full size

stevebrot · 02-21-2018, 12:18 AM

I should add that I have the S-M-C version, but don't have any shots on APS-C. A review of my scans from Ektar 100 and Rollei Retro 100 negatives from a v2 Super Tak 28/3.5 don't show any obvious corner or edge degradation. Some field curvature would not be unexpected in a 28mm of this vintage (most had some), but seeing gross softness on APS-C would be out of character, IMHO.*

I will see what I can do to do a few shots with the K-3.

Steve

* I don't shoot 28mm much on APS-C despite owning three very capable examples that will mount on my K-3. I suppose I should do a "single-in" pledge for the S-M-C Tak 28/3.5.

Alden · 02-21-2018, 10:20 AM

Steve, I have the Version 2, Super Takumar. A gem in hand, but I can't use it, hello paperweight. RAART's picture looks like what I was hoping for. Not the first time the first version was better.

Thanks johnyates for the confirmation.

Steve, I love the 28 i.e. 42mm on a crop sensor, the perfect walk around length.

stevebrot · 02-21-2018, 01:31 PM

Originally posted by Alden

Steve, I have the Version 2, Super Takumar. A gem in hand, but I can't use it, hello paperweight. RAART's picture looks like what I was hoping for. Not the first time the first version was better.

I suspect you either have a bad/damaged copy or are having trouble with focusing. Sorry about the relatively small sizes, but here is the ST 28/3.5 v2 on 35mm film...

While the size (800 pixels on the long side) is a little scant for fine evaluation, gross failure at edge or corner should be visible in these examples. If this is a recent purchase, you might want to contact the seller.

User @jbinpg shoots a fair amount on with the S-M-C 28/3.5 (same optically as your lens) on the K-1 with excellent results. Perhaps they will drop in with their take. The reason why I am being persistent on this is that the v2 is reputed to be a significant improvement over the v1; that and I cannot fault the v2 in the photos I have taken with it. FWIW, my S-M-C version purchase was based on my time with the v2 (on loan along with the Sightseeing Screwmount traveling Pentax SV...LINK).

Steve

Last edited by stevebrot; 02-21-2018 at 01:52 PM.

Alden · 02-21-2018, 03:03 PM

Thanks for the show Steve. I don't think I can evaluate the lens on-line though. I have to pop that 100% on my corners for a look. Even the stellar 35mm has an upper right slightly softer. The sensor frame via the mount has also been cleared of any responsibility, as two 50's are blazingly clear corner to corner. This 28 is a beautiful rendering machine, I just happen to come from medium and large format film and I don't care for any softness where it isn't intended, so I guess it's onto the shelf she goes. Meanwhile a Voigtlander Color Skopar on the Nikon for 28. Leave the 35, and a Yashinon 50 for the Pentax. I like walking with two bodies anyhow, as I hate to change lenses on the fly. Maybe I'll try fishing in the M42 pile. Got my eye's on a Montgomery Ward.

Thanks again for your photographs.

stevebrot · 02-21-2018, 03:53 PM

Originally posted by Alden

I don't think I can evaluate the lens on-line though. I have to pop that 100% on my corners for a look.

It is hard to tell, though I don't expect flat-field performance in any wide-angle lens of that vintage. Some softness away from center is almost unavoidable. My 1980s Tamron 28/2.5 (02B) was advertised as flat-field and demanded a premium price at the time, though I am not sure it would satisfy pixel peep into the corners of even an APS-C crop.

I still suspect your lens has problems and/or is not being properly focused. Evaluation involves a high resolution, high contrast target (e.g. resolution test image) parallel to the sensor plane with the camera located at about half a meter from the target. Focus center using manual focus and magnified live view. Focus confirmation, catch-in focus, and/or the viewfinder matte field are inadequate for critical focus and testing. There might also be a centering issue that may be tested using methods described elsewhere on this site.

Steve

Alden · 02-21-2018, 05:06 PM

I think f/11 should take care off the curvature in most cases, at least the 28 Voigtlander which is my new bar for excellence has no problem. I appreciate tests for the truest evaluation, but field testing is what I stick with because that's where the pictures are. As for not being focused? I might not have the eyes I once had, but focus isn't the problem. I do a number of experiments in areas with ideal practice situations, and push pull focus using several apertures. Some people do assume because it's a wide angle lens that focus is easy, but it's strangely difficult sometimes. I also have the 20mm Voigtlander and it's often very hard to hit the focus perfectly but when you do you know the lens is gold. Glad you said Version 1 was not better, I'll skip it then. Actually I may skip 28mm for the Pentax altogether. Ever notice how too many lenses ends up being too many not getting used?

Alden · 02-22-2018, 05:10 PM

Just a follow up.Tried another copy of the same lens and got the same results. This is an edge challenged lens. Too bad, although for people who don't demand crisp edges it's a beautiful rendering Takumar. Certainly not all photography requires sharpness all over, but for printers like me it's preferred.

stevebrot · 02-22-2018, 06:52 PM

Sorry the ST 28/3.5 v2 did not past muster on your K-5II. I shoot with a K-3 and will spend some time with my copy. If I find it delivers at 24 Mpx, I will post some samples, including full resolution crops, on a separate thread. If you get a chance, you might want to add your experience as a review.

Steve

RAART · 02-22-2018, 09:38 PM

I will have some time on Friday or Saturday and will check my copy of the Super-Tak 28mm (Version 1) and post some pictures here. What distance from the wall will you prefer? What f-stop? Please let me know if you need those.

Gianclaudio · 02-23-2018, 12:14 AM

Go figure..... I experienced something similar (V2 49mm one) with my K-S2 20mp sensor, but found the issue less notorious on my K-01 (similar sensor to yours)

Alden · 02-23-2018, 08:40 AM

I was going to leave the 28mm out of my Pentax line-up as most of my good lenses are Nikon mount, but being the lens junky that I am, I just picked up a Yashica Yashinon 28mm ( DS ) from Austria. $35 for the lens and $45 to ship it. If it's anything thing like the Yashinon 50mm ( DS ) which is stunning, I'll be happy.

02-20-2018, 06:38 PM	#1
Alden New Member Join Date: Feb 2018 Posts: 8	Edge failure on the 28mm F/3.5 M42 mount I picked up a K-5IIs just for the purpose of trying legacy lenses, and read that many people praised the Takumar 28mm f/3.5. I found one in mint condition but was unimpressed by the coverage shot at f/11. While the center is excellent the edges fall away too much to be a usable lens for my taste. I also have the 35mm and it is sharp across the frame. So I was just wondering if I have a bad copy of this 28mm, or are others more forgiving? Can you look at yours at 100% and be satisfied with the sharpness to the sides?

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02-20-2018, 07:27 PM	#2
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Welcome to the Pentax Forums! Which version do you have? Version 1 (1962-1966) has a 58mm filter ring and . Version 2 (1966-1971) has a 49mm filter ring. The two differ in optical design and physical size (Version 2 is smaller). Steve

02-20-2018, 09:44 PM	#3
johnyates Pentaxian Join Date: Aug 2011 Location: Saskatoon, SK Photos: Albums Posts: 1,345	Originally posted by Alden While the center is excellent the edges fall away too much to be a usable lens for my taste. That is my experience with this lens as well.

02-20-2018, 10:38 PM	#4
RAART Veteran Member Join Date: Apr 2013 Location: Oakville, ON Photos: Gallery Posts: 1,095	I do have Version 1 and I do not see so much fall off at the edges... Cannot find pictures now but this one shows at least some leafs on the edge... go on flickr to see full size

02-21-2018, 12:18 AM	#5
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	I should add that I have the S-M-C version, but don't have any shots on APS-C. A review of my scans from Ektar 100 and Rollei Retro 100 negatives from a v2 Super Tak 28/3.5 don't show any obvious corner or edge degradation. Some field curvature would not be unexpected in a 28mm of this vintage (most had some), but seeing gross softness on APS-C would be out of character, IMHO.* I will see what I can do to do a few shots with the K-3. Steve * I don't shoot 28mm much on APS-C despite owning three very capable examples that will mount on my K-3. I suppose I should do a "single-in" pledge for the S-M-C Tak 28/3.5.

02-21-2018, 10:20 AM	#6
Alden New Member Join Date: Feb 2018 Posts: 8 Original Poster	Steve, I have the Version 2, Super Takumar. A gem in hand, but I can't use it, hello paperweight. RAART's picture looks like what I was hoping for. Not the first time the first version was better. Thanks johnyates for the confirmation. Steve, I love the 28 i.e. 42mm on a crop sensor, the perfect walk around length.

02-21-2018, 01:31 PM	#7
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Alden Steve, I have the Version 2, Super Takumar. A gem in hand, but I can't use it, hello paperweight. RAART's picture looks like what I was hoping for. Not the first time the first version was better. I suspect you either have a bad/damaged copy or are having trouble with focusing. Sorry about the relatively small sizes, but here is the ST 28/3.5 v2 on 35mm film... While the size (800 pixels on the long side) is a little scant for fine evaluation, gross failure at edge or corner should be visible in these examples. If this is a recent purchase, you might want to contact the seller. User @jbinpg shoots a fair amount on with the S-M-C 28/3.5 (same optically as your lens) on the K-1 with excellent results. Perhaps they will drop in with their take. The reason why I am being persistent on this is that the v2 is reputed to be a significant improvement over the v1; that and I cannot fault the v2 in the photos I have taken with it. FWIW, my S-M-C version purchase was based on my time with the v2 (on loan along with the Sightseeing Screwmount traveling Pentax SV...LINK). Steve Last edited by stevebrot; 02-21-2018 at 01:52 PM.

02-21-2018, 03:03 PM	#8
Alden New Member Join Date: Feb 2018 Posts: 8 Original Poster	Thanks for the show Steve. I don't think I can evaluate the lens on-line though. I have to pop that 100% on my corners for a look. Even the stellar 35mm has an upper right slightly softer. The sensor frame via the mount has also been cleared of any responsibility, as two 50's are blazingly clear corner to corner. This 28 is a beautiful rendering machine, I just happen to come from medium and large format film and I don't care for any softness where it isn't intended, so I guess it's onto the shelf she goes. Meanwhile a Voigtlander Color Skopar on the Nikon for 28. Leave the 35, and a Yashinon 50 for the Pentax. I like walking with two bodies anyhow, as I hate to change lenses on the fly. Maybe I'll try fishing in the M42 pile. Got my eye's on a Montgomery Ward. Thanks again for your photographs.

02-21-2018, 03:53 PM	#9
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Alden I don't think I can evaluate the lens on-line though. I have to pop that 100% on my corners for a look. It is hard to tell, though I don't expect flat-field performance in any wide-angle lens of that vintage. Some softness away from center is almost unavoidable. My 1980s Tamron 28/2.5 (02B) was advertised as flat-field and demanded a premium price at the time, though I am not sure it would satisfy pixel peep into the corners of even an APS-C crop. I still suspect your lens has problems and/or is not being properly focused. Evaluation involves a high resolution, high contrast target (e.g. resolution test image) parallel to the sensor plane with the camera located at about half a meter from the target. Focus center using manual focus and magnified live view. Focus confirmation, catch-in focus, and/or the viewfinder matte field are inadequate for critical focus and testing. There might also be a centering issue that may be tested using methods described elsewhere on this site. Steve

02-21-2018, 05:06 PM	#10
Alden New Member Join Date: Feb 2018 Posts: 8 Original Poster	I think f/11 should take care off the curvature in most cases, at least the 28 Voigtlander which is my new bar for excellence has no problem. I appreciate tests for the truest evaluation, but field testing is what I stick with because that's where the pictures are. As for not being focused? I might not have the eyes I once had, but focus isn't the problem. I do a number of experiments in areas with ideal practice situations, and push pull focus using several apertures. Some people do assume because it's a wide angle lens that focus is easy, but it's strangely difficult sometimes. I also have the 20mm Voigtlander and it's often very hard to hit the focus perfectly but when you do you know the lens is gold. Glad you said Version 1 was not better, I'll skip it then. Actually I may skip 28mm for the Pentax altogether. Ever notice how too many lenses ends up being too many not getting used?

02-22-2018, 05:10 PM	#11
Alden New Member Join Date: Feb 2018 Posts: 8 Original Poster	Just a follow up.Tried another copy of the same lens and got the same results. This is an edge challenged lens. Too bad, although for people who don't demand crisp edges it's a beautiful rendering Takumar. Certainly not all photography requires sharpness all over, but for printers like me it's preferred.

02-22-2018, 06:52 PM	#12
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Sorry the ST 28/3.5 v2 did not past muster on your K-5II. I shoot with a K-3 and will spend some time with my copy. If I find it delivers at 24 Mpx, I will post some samples, including full resolution crops, on a separate thread. If you get a chance, you might want to add your experience as a review. Steve

02-22-2018, 09:38 PM	#13
RAART Veteran Member Join Date: Apr 2013 Location: Oakville, ON Photos: Gallery Posts: 1,095	I will have some time on Friday or Saturday and will check my copy of the Super-Tak 28mm (Version 1) and post some pictures here. What distance from the wall will you prefer? What f-stop? Please let me know if you need those.

02-23-2018, 12:14 AM	#14
Gianclaudio Senior Member Join Date: Oct 2017 Location: Hannover Photos: Gallery Posts: 163	Go figure..... I experienced something similar (V2 49mm one) with my K-S2 20mp sensor, but found the issue less notorious on my K-01 (similar sensor to yours)

02-23-2018, 08:40 AM	#15
Alden New Member Join Date: Feb 2018 Posts: 8 Original Poster	I was going to leave the 28mm out of my Pentax line-up as most of my good lenses are Nikon mount, but being the lens junky that I am, I just picked up a Yashica Yashinon 28mm ( DS ) from Austria. $35 for the lens and $45 to ship it. If it's anything thing like the Yashinon 50mm ( DS ) which is stunning, I'll be happy.