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Summicron 50mm f2 Type 5 Sharpness


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Hey guys,

 

I recently acquired a cron and decided to do some test shots with it. Was checking if there was any problems with regards to front or back focus but saw that wide open it wasnt that sharp with regards to the center object that I focused on. I attached a photo of the test I did + a cropped photo of the battery I focused on but was not sharp or there was blurriness on the letters. The shot though was done in my dining table with artificial light, f2 ISO100, 2 sec timer to avoid camera shake cause I dont have a tripod at the moment. 

 

I'll definitely shoot during the day when the sun is up to see if theres a difference but just wanted post this and hear your thoughts about this. Maybe the lens needs a calibration or something of the type. Kinda new to Leica lenses as this is my first M lens. 

 

Thank you 

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Hi!

 

A well calibrated Cron V should be sharper imho. On which body did you shoot this pic? At what distance? (Tape measure from sensor plane). Is this effect consistent at same distance? Consistent across varying distance?

 

If it was a Live View capable body, you could first compare rangefinder focus vs LV zoom focus to check whether lens, rangefinder or focus technique is at fault.

 

My Cron 50 V is very sharp (although not as razor sharp as my apo), even on my M10. I mostly use it on film (M7, M3) though. It is not at it‘s best at f/2, even f/2.8 will improve overall IQ, many would advise f/4. However, as previously stated, results at f/2 should be better than your sample image. And do borrow a tripod from a friend.

 

EDIT: I find those inexpensive foldable paper targets very helpful for hunting down focus issues. A ruler set at 45 degrees will do the same.

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Edited by schattenundlicht
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Need to say if this is RF focussed or Live View.

 

If RF, are there other lenses you have you know to be sharp wide open? This to confirm the RF is in calibration.

 

Do a yard stick test. Tape a target such as a paper clip to the mid point of a yard stick. Put the camera on a tripod with the lens near the minimum focus distance. Move the yard stick (longitudinally to the camera) back and forth checking the RF patch for focus. When focus is confirmed make an exposure and check the file in a computer for sharpness or focus either front or back of actual plane of focus.

 

Can you tell by the retaining rings of the lens if it has been opened-up and perhaps the put out of calibration.

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Put on the table or not - there is still camera shake in that image. Your camera slid or twisted on the polished wood. See double image of battery tip.

 

That being said, the regular (non-APO) 50 Summicron is pushing 40 years old as a design (the type 5 is just the type 4, in a new barrel with built-in shade). It is a very good design, but not state-of-the-art aberration control @ f/2.0 and at closest focus.

 

From Erwin Puts' Compendium: "[it] delivers outstanding performance at a close-up distance when stopped down a bit" and "at f/4 we have an outstanding image quality."

 

OTOH, find a 50mm f/2.0 lens that small and/or light from anyone else (including the Summicron for the SL - eeek!).

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I have both the 50 'Rigid' (purchased new with an M4 in 1968) and a current 50 Summicron. I no longer use the 'Rigid' since I have the newer lens, but there is really nothing wrong with the older model which served me well for all those years.

 

As of the test shot, the OP does need to refine his technique. A tripod is definitely must; a proper target, properly positioned is also needed. An fairly easily built target can be downloaded from the following site:

http://squit.co.uk/photo/focuschart.html

 

Since I do use a tripod for some of my work, I purchased replacement baseplates from RRS for my M9 and M-P

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Without wishing to take over this thread, but still tying it in with "Summicron 50mm f2 Type 5 sharpness" so hopefully it is useful to the OP, i'd be grateful what your thoughts are on this ....the image was taken with this Summicron v5 lens + M 240 at f4.8.  

I'm unsure what we see here is "normal" for this lens (eg, it simply has very, very high field curvature), or if it is "faulty" (eg, decentred?; or showing excessive field curvature?; or has some other fault? - such that my copy of this lens needs fixing?)

 

I show a photo of the "whole scene" as an example, which is a distant landscape in Chamonix.  If you assume the image is 20" across its full width, i'd say:

 

- the middle 10" section is very sharp (see crop), BUT

- both of the sides of the image (5" on each side, ie, 10" of the entire image) are obviously blurry (see other crop).

 

Both sides are about as blurred as each other at f 4.8.

 

Any thoughts, or more ideas on how to diagnose what is going on here, would be hugely appreciated!

 

 

 

 

 

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Unless you can show that the image is actually sharp - but in a different plane - you probably are not seeing/showing "field curvature." Some lenses are simply softer away from the center, due to other aberrations than field curvature (coma and astigmatism being the most common).

 

Here's Leica's own MTF chart for the current 50 'cron. See those big dips in the dashed lines over on the right (outer edge) even at f/5.6? Tangential details (lines concentric to the image center) are still dropping in contrast substantially - not much better than f/2.0 near the edge. That'll mean smearing in the direction from the center to the corners. Over just about the outer "half" of the image, as you say.

 

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Erwin Puts describes the v. 4/5 as having "improved performance" over the v.3 regarding curvature of field and coma - which is a back-handed way of saying "but still not perfect."

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Many thanks Adan for your reply.

I've looked at some more of my images with this lens .....

What this lens is creating appears to be a VERY aggressive horse shoe shape for what is sharply in focus ....ie, if i focus on infinity, the middle of the image is sharp .... but the sides at infinity are blurred ..... BUT the sides NOT at infinity (ie, at the sides of the image that are very near to the camera, ie, just a few metres away) are also sharp!!!

I assume this is field curvature, but is it typically THAT extreme with this lens? If not, what's going wrong?

Thanks again

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Jon what you are describing I do not recognize at all in my copy of the Summicron 50mm (type V).

I could not find a picture focused at infinity, I do not seem to make many of them!

This picture however shows that this lens has no particular problem in the zone or corners also not when viewed at 100%.

 

 

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Considering weight & size, for real life photograph, imho the Cron 50 IV/V still is a very good lens. I like it very much to „detox“ from my more characterful lenses or extreme focal lengths. This lens tends to recalibrate my eye to the quintessential („das Wesentliche“) of photography.

 

It would be disconcerting, however, if lens design and engineering had not moved on since the 1970ies ;)

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I suspect you can thank digital imaging for most of that. I certainly do.

Actually, I was more thinking of the vast improvements in computer hard- and software that, over the last decades, have allowed lens designers to simulate design changes more precisely and to reiterate multiple design variations with increasingly negligible time penalty...

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[...] Both sides are about as blurred as each other at f 4.8.

Any thoughts, or more ideas on how to diagnose what is going on here, would be hugely appreciated!

 

I don't focus at infinity usually and i have no 50/2 on hand but i would suggest this if you can shoot another remote landscape: focus a bit closer and check if your corners are sharper. If so, a good explanation will be field curvature probably.

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Actually, I was more thinking of the vast improvements in computer hard- and software...

 

True - and the Leica SL and APO-M 50 Summicrons are designed that way (and priced that way).

 

As an aside, showing a picture at the size of a large iPad just reveals nothing important about fine sharpness and clarity. Jon's "whole picture" example looks fine, also - he had to show us the cropped details to reveal what was troubling him.

 

Jon, to me, what you are getting is about what I've always seen from the v.4/5 Summicron. Prior to the Summarit lenses, it has always been Leica's "entry-level" M lens - the cheapest in the line. The one they used to throw into a kit with an M body, total price discounted $500/£400. Designed to a price point, and to work very well on middle-ISO gelatin film. - 60%+ contrast at 40 lppm, over most of the picture, at f/5.6.

 

It is also what I was getting at in the "End of the M" thread - don't get too excited about 48 Mp until you have actually tried some of the M lenses, especially the ones designed in the film era and not revised for digital. There's a reason the APO-Summicron costs 3 times as much as the base Summicron.

 

The only authoritative "second opinion" you can get is to send this lens to Leica themselves and ask if it is performing within specs. My experience says that they will say "Yes, that is within specs at f/4.8."

 

The good news is that this is "gaussian" blurring that responds rather well to digital sharpening algorithms, up to a point.

Edited by adan
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Well, I wouldn't agree the 50 Summicron was the "entry level" Leica lens - that was the 50 Elmar for us old-timers. When I bought my M4 in 1968 the 50 2.8 Elmar was $78, about half the price of a Summicron 50, though that was the v2 or 3 Summicron. The Elmar was off the books for some time, but before the 2.5 Summarit the entry was the the 50 2.8 Elmar-M, which is also a more than decent performing lens.

But the O.P.s shot doesn't look typical, and does show a double image that looks like motion blur. Just for comparison here's a 100% crop of an AA cell, also a dining table shot, handheld, and just an OOC jpeg of my Summicron v5 at f2, minimum focus distance:

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I just took one try, even with my not-as-steady-as-I-used-to-be hands.

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2 second without tripod. And without delay, cable, I guess....

And my Cron IV has focus shift between f2.8 and f5.6. 

No idea why it was labeled as entry lens here. Elmarit-M 50 2.8 and Summarit-M 50 2.5(4) should ring the bell.  

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You know there is a reason some guy didn't just pluck it out of the air when he said the path to success is 'f/8 and be there'. 

 

Picture Editors are a mean lot, when they say 'this is out of focus' it just doesn't cut it to say back 'it's field curvature boss'. So this thread reads like a list of things people have forgotten, or never knew, oh and trying to defy the laws of physics, so just suck it up and buy a tripod guys because it solves most of the 'problems' with lenses. But on the other hand, who looks at the corners of a picture anyway, that's where you hide your signature isn't it........................?

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