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I was wondering which of my 50mm something lens was - -
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PostPosted: Sat Oct 23, 2010 3:49 pm    Post subject: I was wondering which of my 50mm something lens was - - Reply with quote
- sharpest wide open. I took eight lenses & shot a test panel with the camera on a tripod & using a cable release. To my great surprise there was very little difference at all in the images in spite of the largest apertures varying between f1.4 & f3.5

Here are three examples:

1.




2.




3.





Would you pick one over the other?


PostPosted: Sat Oct 23, 2010 3:54 pm    Post subject: Re: I was wondering which of my 50mm something lens was - - Reply with quote
revers wrote:

Would you pick one over the other?


Not at that image size. Wink


PostPosted: Sat Oct 23, 2010 4:01 pm    Post subject: Re: I was wondering which of my 50mm something lens was - - Reply with quote
LucisPictor wrote:
revers wrote:

Would you pick one over the other?


Not at that image size. Wink


At that size,
sharpnesswise it's 1. 3. 2. for me.

2nd has poor resolution at the edges.


PostPosted: Sat Oct 23, 2010 9:00 pm    Post subject: Re: I was wondering which of my 50mm something lens was - - Reply with quote
hasan wrote:
LucisPictor wrote:
revers wrote:

Would you pick one over the other?


Not at that image size. Wink


At that size,
sharpnesswise it's 1. 3. 2. for me.

2nd has poor resolution at the edges.


+1

Hard to tell at that size. But....

1) Minolta 50 1.4 would be my guess.


PostPosted: Sat Oct 23, 2010 9:04 pm    Post subject: Reply with quote
Maybe focus shift. Refocus at all f-settings for comparing!

Klaus


PostPosted: Sat Oct 23, 2010 9:25 pm    Post subject: Reply with quote
Quote:
2nd has poor resolution at the edges.


Agreed at that size not much difference, though #2 is definitely poor near the edges in these shots.


PostPosted: Sat Oct 23, 2010 9:31 pm    Post subject: Reply with quote
One problem with this test is that you only test one subject distance. Different lenses tend to be optimized for different optimal operational focus range.


PostPosted: Sat Oct 23, 2010 10:59 pm    Post subject: Re: I was wondering which of my 50mm something lens was - - Reply with quote
walter g wrote:




Hard to tell at that size. But....

1) Minolta 50 1.4 would be my guess.



The Minolta 50/1.4 was one in the test but is not one shown here.

1. Super Takumar 55/1.8

2. Helios 44-2, 58/2.0

3. Sears 50/2.0

I selected three to show with close maximum apertures.


I am not sure what Klaus is saying but each lens was carefully focused on the centre circle @ the maximum aperture for each lens.


PostPosted: Sat Oct 23, 2010 11:20 pm    Post subject: Re: I was wondering which of my 50mm something lens was - - Reply with quote
hasan wrote:
LucisPictor wrote:
revers wrote:

Would you pick one over the other?


Not at that image size. Wink


At that size,
sharpnesswise it's 1. 3. 2. for me.

2nd has poor resolution at the edges.


+1

N° 1 very good corner resolution.


PostPosted: Sat Oct 23, 2010 11:23 pm    Post subject: Reply with quote
Hi Ron.

Thanks for the test.

Please, tell me, which version (or number) of the 1,8/50 S.T.

Rino


PostPosted: Sat Oct 23, 2010 11:35 pm    Post subject: Reply with quote
Anu wrote:
One problem with this test is that you only test one subject distance. Different lenses tend to be optimized for different optimal operational focus range.


I demonstrated what you say today with two 35-70mm lenses, a Kalimar & a Soiigor. I shot the same test panel with both wide open @ 35 & 70mm.

The Kalimar was sharp @ 35mm & soft @ 70mm,
the Soligor was soft @ 35mm & sharp @ 70mm.

I bought the Soligor after trying it in a camera shop after testing it against two other lenses wide open @ 70mm. Now I wonder if I made the correct decision.


PostPosted: Sat Oct 23, 2010 11:40 pm    Post subject: Reply with quote
estudleon wrote:
Hi Ron.

Thanks for the test.

Please, tell me, which version (or number) of the 1,8/50 S.T.

Rino


It is M42, SN 1691494.

Is this what you want ?


PostPosted: Sun Oct 24, 2010 12:34 am    Post subject: Reply with quote
Anu is right, photographing these charts has little to do with what the lenses were optimized for, which is usually (except for macro lenses) photography at infinity. It is possible that at infinity the performances may even be reversed.

Also, in order to express any opinion, full size pictures should be provided. The only thing that is maybe possible to say from an 800 pixels image is how the rezise algorhythm of the software did it's job.


PostPosted: Sun Oct 24, 2010 1:09 am    Post subject: Reply with quote
Orio wrote:
Anu is right, photographing these charts has little to do with what the lenses were optimized for, which is usually (except for macro lenses) photography at infinity. It is possible that at infinity the performances may even be reversed.

Also, in order to express any opinion, full size pictures should be provided. The only thing that is maybe possible to say from an 800 pixels image is how the rezise algorhythm of the software did it's job.


I understand what you are saying but I contend the smaller files still represent the difference in the originals but on a smaller scale. Furthermore, this site still sets a limit on what file size is acceptable to upload directly, certainly not the full size. As my internet connection is very slow, I try to make the best of what I can do with more than one photo per post.


PostPosted: Sun Oct 24, 2010 1:30 am    Post subject: Reply with quote
revers wrote:

I understand what you are saying but I contend the smaller files still represent the difference in the originals but on a smaller scale.


The problem is that sharpness is related to scale. When you mess with the scale, you also mess with the sharpness. That is why sharpness is always evaluated at 100% size. The direct upload limit can be dealt with by posting 100% size crops of the critical areas.


PostPosted: Sun Oct 24, 2010 1:41 am    Post subject: Reply with quote
Orio wrote:
revers wrote:

I understand what you are saying but I contend the smaller files still represent the difference in the originals but on a smaller scale.


The problem is that sharpness is related to scale. When you mess with the scale, you also mess with the sharpness. That is why sharpness is always evaluated at 100% size. The direct upload limit can be dealt with by posting 100% size crops of the critical areas.


In this case do you really think that would change the rating of 1-3-2 which seems unanimous. I don't.


PostPosted: Sun Oct 24, 2010 1:58 am    Post subject: Reply with quote
revers wrote:

In this case do you really think that would change the rating of 1-3-2 which seems unanimous. I don't.


The only sure thing that I can tell from your images is that your second image (most likely the f/1.4 lens) has obvious blur on the right side edge, which may be caused either by the sensor plane not being perfectly parallel to the chart, or (I hope not) by a slight misaligned element in your lens, or imperfect glass element.

For the rest, I notice in all three images a moire pattern on the 5 lpm square, which may have been caused either by the camera sensor, or by the resize algorhythm (resize-induced moire). Impossible to tell the reason why without looking at the 100% size image. Resize may, or may not, have completely altered the result. Not having the certainty, judgement must be suspended.

The second thing I notice is that all three images create a blurry mess (that turns into an almost solid gray) at the 8, 9 and 10 lpm squares. And again, impossible to tell if this is caused by the lens or sensor not able to resolve, or, if it's caused by the resize having merged lines that in the full image were separatedly discernible. Which, again, brings us back to the resize problem. And to the suspension of judgement.

If I was not aware of the inutility of judging sharpness on resized images, and wanted to give an opinion based only on these 800 pixels images, I would say -based on the observation of those 5 and 8/9/10 lpm squares- that the three lenses perform exactly the same.
But reasonable chances are that if I could look at the 100% images, differences may have surfaced.


PostPosted: Sun Oct 24, 2010 2:52 am    Post subject: Reply with quote
revers wrote:
Orio wrote:
revers wrote:

I understand what you are saying but I contend the smaller files still represent the difference in the originals but on a smaller scale.


The problem is that sharpness is related to scale. When you mess with the scale, you also mess with the sharpness. That is why sharpness is always evaluated at 100% size. The direct upload limit can be dealt with by posting 100% size crops of the critical areas.


In this case do you really think that would change the rating of 1-3-2 which seems unanimous. I don't.


I think this is being judged mainly by corner sharpness. That's how I judged.

But if you did crops of the center, and only judged off that.
I think the order would be 2-1-3. The center really need to be larger for accurate judging. There are differences.
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