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SMC Pentax 50/1.4 vs Topcor 58/1.8
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PostPosted: Sun Apr 08, 2018 7:49 pm    Post subject: Reply with quote

tb_a wrote:
Out of curiosity I've now compared my Super Takumar 50mm/F1.4 with my RE.Auto Topcor 58mm/F1.8 lens. Additionally I took my Minolta MC 58mm/F1.2.

My conclusion is that indeed in pixel peeping mode the Takumar beats the Topcor at least until F4.
...
I've compared them on my Ricoh GXR-M APS-C camera without AA-filter and at least on APS-C all of these old lenses deliver stunningly sharp pictures already as from F2.8 from edge to edge. IMHO more than good enough for landscape and architecture.


That's certainly true for the cropped sensor. On FF, things look different. I have re-done my original test, this time with three 1.4/50mm Takumars and three 1.8/58mm Topcors.
Two of the Takumars were early ones with a metal focusing grip and strong yellow color cast (thorium lenses), the third Takumar was a later M42 version with rubber focusing grip and less strong color cast, obviously a different optical design (mid 1970).

The results are consistent; all three Topcors perform equally well (indistinguishable on 24MP FF); the two early Takumars perform identically, and the third (later) Takumar is slightly worse than the earlier two.

I have added the 100% crops from these test, taken at f1.5, f2 and f4, respectively.

Stephan

PLEASE CLICK / DOWNLOAD TO SEE THE IMAGE BELOW IN FULL SIZE!!



PostPosted: Sun Apr 08, 2018 7:56 pm    Post subject: Reply with quote

Corners better with the Topcors here.


PostPosted: Sun Apr 08, 2018 8:12 pm    Post subject: Reply with quote

stevemark wrote:
That's certainly true for the cropped sensor. On FF, things look different. I have re-done my original test, this time with three 1.4/50mm Takumars and three 1.8/58mm Topcors.
Two of the Takumars were early ones with a metal focusing grip and strong yellow color cast (thorium lenses), the third Takumar was a later M42 version with rubber focusing grip and less strong color cast, obviously a different optical design (mid 1970).

The results are consistent; all three Topcors perform equally well (indistinguishable on 24MP FF); the two early Takumars perform identically, and the third (later) Takumar is slightly worse than the earlier two.

I have added the 100% crops from these test, taken at f1.5, f2 and f4, respectively.

I'm afraid you can't judge the Pentax's optical design by its color cast amount. The S-M-C (all metal knurled grip) Takumars, later SMC (rubber grip) Takumars and PK SMC Pentax (K line) share the optical design - except for minor progress in coating tech. The amount of color cast depends on usage pattern - it gets yellower when the lens is not used (no UV rays).

Unfortunately, all the Topcors of yours share the same optical design judging from their serials - 116xxxxx. That one should be the most advanced optical design employed for the 58/1.8.


PostPosted: Sun Apr 08, 2018 8:54 pm    Post subject: Reply with quote

stevemark wrote:
tb_a wrote:
Out of curiosity I've now compared my Super Takumar 50mm/F1.4 with my RE.Auto Topcor 58mm/F1.8 lens. Additionally I took my Minolta MC 58mm/F1.2.

My conclusion is that indeed in pixel peeping mode the Takumar beats the Topcor at least until F4.
...
I've compared them on my Ricoh GXR-M APS-C camera without AA-filter and at least on APS-C all of these old lenses deliver stunningly sharp pictures already as from F2.8 from edge to edge. IMHO more than good enough for landscape and architecture.


That's certainly true for the cropped sensor. On FF, things look different. I have re-done my original test, this time with three 1.4/50mm Takumars and three 1.8/58mm Topcors.


One more reason that I couldn't care less about test reports from a Sony A7. Wink

I had recently a similar discussion about another 50mm SLR lens pair comparison with totally different results from different cameras and I start to believe that the A7 is very specific and somehow unique in terms of adapted lens performance, particularly in the corners and not only with RF lenses. Not even my old Sony A850 which I use sometimes with old adapted M42 lenses is performing that strange although it's equipped with a similar FF sensor.

In other words: If I compare 2 different M42 lenses on both of my APS-C and FF cameras I never had contradictory results so far (Ricoh GXR-M vs. Sony A850) and this is actually the second case that the A7 delivers something different. Unfortunately I'm not able to test the Topcor on the A850. However, I will certainly recheck my Takumar in the corners on my FF camera again.

Stephan, thanks a lot for your presentation.


PostPosted: Mon Apr 09, 2018 8:28 am    Post subject: Reply with quote

tb_a wrote:

...
I had recently a similar discussion about another 50mm SLR lens pair comparison with totally different results from different cameras and I start to believe that the A7 is very specific and somehow unique in terms of adapted lens performance, particularly in the corners and not only with RF lenses.


Of course, the Sony E system has its problems caused by the Filter stack (2.5mm thick, nD 1.51, Abbé number 64.2). However, these problems are limited to wideangle rangefinder lenses. I have checked fast SLR lenses such as the Minolta MD 1.2/50mm, and fast SLR wideangles such as the MD 2/28mm on both the Leica M240 (0.9mm Filter stack) and the Sony A7RII (2.5mm filter stack). Lens performance was identical. And Tele lenses are even less critical.


tb_a wrote:

Not even my old Sony A850 which I use sometimes with old adapted M42 lenses is performing that strange although it's equipped with a similar FF sensor.

It is possible (and even probable) that the A850/A900 has a thinner filter stack than the A7/A9 system. Canon's early professional DSLRs used to have something like 1.5mm, and Nikons D100 was at only 0.75mm! And micro 4/3 is in the range of >4mm!!

tb_a wrote:

In other words: If I compare 2 different M42 lenses on both of my APS-C and FF cameras I never had contradictory results so far (Ricoh GXR-M vs. Sony A850)

That's possible, but that's certainly by chance. If you look at measured MTF curves eg from the Zeiss CY Distagon 4/18mm, its performance is quite even from the center to 15mm image height (APS-C corners), but drops drastically at 22mm image height (FF corners). This has nothing to do with the camera; it's an intrinsic property of the lens itself.


tb_a wrote:

I will certainly recheck my Takumar in the corners on my FF camera again.


Me too Wink ... and i predict that my 1.4/50mm Takumars will have the same corner resolution problems on the A900. And on film of course, but that's another story.

Stephan


PostPosted: Mon Apr 09, 2018 9:38 am    Post subject: Reply with quote

Thanks for your comments, Stephan.

I've skipped my plans to go for any A7 camera until further anyway. I've too many RF lenses in my collection already. I'll rather go for the Voigtlaender Hyper Wide Heliar 10mm/F5.6 for my Ricoh and a Minolta AF 400mm/F4.5 APO G HS for my A850 instead. IMHO in the long run the far better investments.


PostPosted: Fri Apr 13, 2018 9:05 pm    Post subject: Reply with quote

The Topcor lenses do have field curvature -- that's their design compromise.

On the other hand, the Sony a7 cameras like lenses with field curvature. All their lenses have field curvature to match the sensor.


PostPosted: Sat Apr 14, 2018 11:10 am    Post subject: Reply with quote

It seems I have a weak Topcor. sn 11660794. At least on the A7. My copy looks to have strong field curvature.


PostPosted: Sat Apr 14, 2018 3:16 pm    Post subject: Reply with quote

I take back my previous statement.

Topcor 1.8/58


#1



SMC Takumar 1.8/55


#2



topcor



takumar



PostPosted: Sat Apr 14, 2018 10:31 pm    Post subject: Reply with quote

Is there a problem with your lens mounts. Neither of those images looks right to me at any aperture.
I find it hard to believe that both of your lenses could be defective in some way
Tom


PostPosted: Sat Apr 14, 2018 11:25 pm    Post subject: Reply with quote

Oldhand wrote:
Is there a problem with your lens mounts. Neither of those images looks right to me at any aperture.
I find it hard to believe that both of your lenses could be defective in some way
Tom


These are crops from the left side, with the center in focus. Taken with my Sony A7 so full frame. There is nothing obvious wrong with the lenses. I'm not sure what's up.


PostPosted: Sat Apr 14, 2018 11:38 pm    Post subject: Reply with quote

blotafton wrote:
Oldhand wrote:
Is there a problem with your lens mounts. Neither of those images looks right to me at any aperture.
I find it hard to believe that both of your lenses could be defective in some way
Tom


These are crops from the left side, with the center in focus. Taken with my Sony A7 so full frame. There is nothing obvious wrong with the lenses. I'm not sure what's up.

Yes a puzzle to me too
Tom


PostPosted: Sun Apr 15, 2018 3:06 pm    Post subject: Reply with quote

Off topic but.
My image posts with a Zuiko 55 1.2, Prakticar 50 1.4, Meyer 50 1.8 and Riconar 55 2.2 also got comments that they were defective.
It must be something else than the lenses.


PostPosted: Sun Apr 15, 2018 3:48 pm    Post subject: Reply with quote

A lens can perform differently on sensor size and different magnification. Sometime, the use of a proper hood and lighting conditions may have significant impact on the photo. The lens may look defective to one but not the others.


PostPosted: Sun Apr 15, 2018 6:18 pm    Post subject: Reply with quote

John Shriver wrote:

On the other hand, the Sony a7 cameras like lenses with field curvature. All their lenses have field curvature to match the sensor.


The lenses we're talking about look exactly the same on a Leica M9/M240 (extremely thin sensor glass) and the Sony A7 24MP series (2.5mm glass).

Stephan


PostPosted: Tue Apr 24, 2018 11:08 am    Post subject: Reply with quote

stevemark wrote:
John Shriver wrote:

On the other hand, the Sony a7 cameras like lenses with field curvature. All their lenses have field curvature to match the sensor.


The lenses we're talking about look exactly the same on a Leica M9/M240 (extremely thin sensor glass) and the Sony A7 24MP series (2.5mm glass).

Stephan


Because I've changed my mind I've acquired a A7R2 recently and out of curiosity I've redone the comparison on my new FF camera as these lenses are still lying around...

Interestingly I've got exactly the same result as from my Ricoh APS-C camera; i.e. up to F4 the Takumar is better in the corners at same apertures and as from F4 the lenses aren't distinguishable anymore.

However, I've used proper lens hoods on both lenses and shot at lowest ISO from a sturdy tripod at highest resolution uncompressed RAW. Maybe the much higher resolution of the A7R2 in combination with the lack of the low-pass filter is the decisive factor here.


PostPosted: Tue Apr 24, 2018 2:17 pm    Post subject: Reply with quote

@tb_a

Do you happen to have a Rikenon XR 50/2.0? I’m very curious how it performs on an A7II.
From tests with my E-pl5 it seems to be a strong performer. I’m curious about its corner performance.


PostPosted: Tue Apr 24, 2018 2:28 pm    Post subject: Reply with quote

caspert79 wrote:
@tb_a

Do you happen to have a Rikenon XR 50/2.0? I’m very curious how it performs on an A7II.
From tests with my E-pl5 it seems to be a strong performer. I’m curious about its corner performance.


Sorry, although I have rather many lenses, I don't have any Rikenon.


PostPosted: Wed Apr 25, 2018 8:53 am    Post subject: Reply with quote

calvin83 wrote:
A lens can perform differently on sensor size and different magnification. Sometime, the use of a proper hood and lighting conditions may have significant impact on the photo. The lens may look defective to one but not the others.


I am sure you are correct, I have a Sony NEX 5t & A6000. I have noticed that the NEX's 16 meg pics are more vibrant & have more contrast when compared to the A6000 24 meg when using the same lens? I have checked several times to make sure both cameras have the same settings?

Both are equally as sharp & the quality of the photo's are good, just the A6000 looks a little bit washed out prior to any adjustments in Lightroom. After processing both end up almost the same. I have tested this a few times, same lighting, same subject, same lens just swapped cameras. It is not a problem, just an observation.


PostPosted: Thu Apr 26, 2018 6:35 pm    Post subject: Reply with quote

tb_a wrote:

Because I've changed my mind I've acquired a A7R2 recently
...
Interestingly I've got exactly the same result as from my Ricoh APS-C camera; i.e. up to F4 the Takumar is better in the corners at same apertures and as from F4 the lenses aren't distinguishable anymore.
...
Maybe the much higher resolution of the A7R2 in combination with the lack of the low-pass filter is the decisive factor here.


I don't think there's such a difference between A7 and A7RII. The sensor pack of both cameras has the same thickness (2.5mm).
Since my three RE Topcors 1.8/58mm are indistinguishable from each other, and so are my two early 1.4/50mm Takumars, i suspect we have different designs - either yout Topcor or your Takumar probably has an earlier or updated computation. It was quite common in those days to improve performance of a certain lens without advertising it. We know for sure that Minolta did this with their 1.4/58mm lenses; Nikon had quite a few slightly different 1.4/50mm lenses, and there are different versions of the Topcor 1.8/55mm. I don't know about the Pentax, but i would assume they did the same.

Stephan


PostPosted: Thu Apr 26, 2018 11:47 pm    Post subject: Reply with quote

caspert79 wrote:
@tb_a

Do you happen to have a Rikenon XR 50/2.0? I’m very curious how it performs on an A7II.
From tests with my E-pl5 it seems to be a strong performer. I’m curious about its corner performance.


I have one. I could put it on my K-1

edit: Here http://forum.mflenses.com/viewtopic,p,1511161.html#1511161


PostPosted: Sat Sep 23, 2023 9:28 pm    Post subject: Reply with quote

I am going to resurrect this old thread and add some information to consider.

So far in this thread the following factors have been brought up: The optical formula changing, differences in sensor stack thickness, and curvature. These are all possibilities.

Curvature is one of the more interesting characteristics of a lens. Here is an article from lens rentals about center focus MTF vs best average focus MTF. In certain cases, and certain curvature, you can make minor adjustments to better balance the sharpness throughout the frame at the expense of sharpness at the center.

https://www.lensrentals.com/blog/2017/11/testing-lenses-finding-the-best-average-focus-point/

Take the human factor out of it in terms of how someone focused, and I think we need to consider the length of the adapter which can vary but tends to often fall into the slightly too short range. When it comes to lenses with floating or aspheric lens elements, they are more sensitive to adapter length. I have also read that this is the case with curvature. If I understand the lens rentals article correctly, then a difference of 0.05mm changed the MTF in a meaningful way. This is very much within range of what we see in cheap adapters.

Quote:
Then we focused 0.05mm further than the best center point focus and ran the MTF again


Look at the illustration under this section for a visual representation:

Quote:
To give a more intuitive picture, I’ll draw a second bar across the Field graph from above in green, at +0.052mm.


PostPosted: Sat Sep 23, 2023 10:32 pm    Post subject: Reply with quote

cbass wrote:
I am going to resurrect this old thread and add some information to consider.

So far in this thread the following factors have been brought up: The optical formula changing, differences in sensor stack thickness, and curvature. These are all possibilities.

Curvature is one of the more interesting characteristics of a lens. Here is an article from lens rentals about center focus MTF vs best average focus MTF. In certain cases, and certain curvature, you can make minor adjustments to better balance the sharpness throughout the frame at the expense of sharpness at the center.

https://www.lensrentals.com/blog/2017/11/testing-lenses-finding-the-best-average-focus-point/

Take the human factor out of it in terms of how someone focused, and I think we need to consider the length of the adapter which can vary but tends to often fall into the slightly too short range. When it comes to lenses with floating or aspheric lens elements, they are more sensitive to adapter length. I have also read that this is the case with curvature. If I understand the lens rentals article correctly, then a difference of 0.05mm changed the MTF in a meaningful way. This is very much within range of what we see in cheap adapters.

Quote:
Then we focused 0.05mm further than the best center point focus and ran the MTF again


Look at the illustration under this section for a visual representation:

Quote:
To give a more intuitive picture, I’ll draw a second bar across the Field graph from above in green, at +0.052mm.


Like 1 Like 1 Thank you! for the link!

Compare BAF MTF Position test results with center-focus test results anybody?


PostPosted: Sun Sep 24, 2023 10:18 am    Post subject: Reply with quote

Lightshow wrote:
I'll post the serial # info from another post.
Code 62B based on the F Auto-Topcor from: 620001 to 625115 (1963)
Code 99B new optics,2nd and 3rd elements were separated. from 99xxxxx to 9901920 (1964)
Code 116B new mechanicals, from 1160001 to 11608302 (1965)
Code 129B (black or chrome) optics changed again From: 1161xxxx to 11670435 last known (1966) I have the chrome version, awesome lens.
Code 129BD (Navy) from: 1165xxxx to 11650401 last known (1967)
Code 129BG AUTO-TOPCOR (black) from: 1168xxxx to 11685922 last known (1971)


Just received a damaged in shipping 11658... black version with Chrome front ring, what code would it fit into?
It is the RE Auto-Topcor 1:1.8 f=5,8cm


PostPosted: Sun Sep 24, 2023 2:52 pm    Post subject: Reply with quote

129BG