Canon 50mm f/1.5 LTM sharpness wide open?

p-c

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Hi,
How does the Canon 50mm f/1.5 LTM lens compare to its double gauss siblings (preferably the 50/1.4 and the 50/1.8) with regard to sharpness wide open? I'm not sure what to expect from this lens at the widest aperture. My copy lags considerably behind the other two in terms of wide open sharpness. While I get tack sharp pictures with the 50/1.4 and the 50/1.8, I find that the widest aperture I can use with my Canon sonnar is f/2 for acceptable sharpness. What is your experience with it's wide open performance?

Thanks in advance!
 
Is your lens "Glowy" wide open?
I found only the Zeiss Opton f1.5/50mm to be relatively free from glow at full aperture when considering Sonnar lenses from that era.
It can and maybe should be considered a feature rather than a flaw of those lenses.
In lower light the glow is usually less noticeable and could help open shadows.
Originally Fast apertures were meant for low light and slow film.
My old Nikon f1.4/50 was also glowing and looked unsharp(ish) at widest aperture.

For comparison, Double Gausse lenses have more appearance of sharpness at similar apertures with less glow and higher contrast.

Here is an Opton sample at wide open. My Old iiia had a shutter capping issue.


She gets there eventually. by Adnan, on Flickr
 
I had a Canon 50/1.5 lens years back, but sold it when I bought my Canon 50/1.4. Wide-open, I think the 50/1.4 is sharper.

But remember that Sonnar-based lenses will exhibit focus shift wide-open. Most likely that contributes to some of the unsharpness you may see.

Jim B.
 
The Canon 50mm f1.4 lens is sharper wide open than the Canon f1.5, heck the Nikkor f 1.4 wide open is sharper than the Canon f 1.5 if you don't mind the occasional veiling flare.

In my opinion the Canon f 1.5 lens comes at its own at around f2.8, very similar to a good Jupiter 3 and even similar to the Zeiss Sonnar f1.5,( which is no surprise) although I found the Sonnar has unpleasant flare wide open, maybe that is just my sample and not an indication of every original 5cm f1.5 speed Sonnar lens.
 
Define "acceptable sharpness"; acceptable for what? Mine is plenty sharp for any sort of reasonable print size. Not as sharp as a double Gauss design can be, in a clinical sense at least, but honestly, how sharp does it need to be? The focus shift issue mentioned above may indeed be a factor, but beyond that and ensuring that the lens is clean and properly assembled, sharpness shouldn't be a problem unless you're printing wall-sized murals.
 
The Canon 1.5 is sharp, even wide open. It has no flare if you get a good copy with no scratches or haze. The Canon at 1.5, Jupiter 1.5, and Nikkor at 1.4. They all have a Sonnar look (sharp with weird bokeh). The Nikkor is the softest wide open. The Canon 1.4 is a totally different design, and a lot bigger.

8469632978_38178c30db_c.jpg


8469635384_7f72f3b3d5_c.jpg


8469637716_373e9b2494_c.jpg
 
The Canon 50mm f1.5 is like most of the sonnars..
wide-open: fairly sharp in the center, but not sharp outside. a bit of swirl.
Stoped down to f2, nicely sharp in the center and better in the edges.
At f2.8, very sharp in the center and pretty sharp out to the edges.
And it just gets better.
i havent seen any indication of focus shift.

The canon lenses often have a hazy buildup that needs to be cleaned. The cleaning can easily leave marks.
Sometimes this is fungus not haze and that can etch the internal surfaces.
 
Thanks all for your replies!

f16sunshine, my copy doesn't have much glow wide open. It's a very clean lens, considered a "mint minus" from the seller. My 1951 jupiter-3 however...!

Mackinaw, I'm aware of the possibility of focus shift, but does it apply for digital cameras as well? I'm using both a Canon P and the Fuji X-T1.

xayraa33, I have two Jupiter-3's, from 1951 and 1955. the later one is really sharp wide open and not very glowy. My other russian sonnar, a Jupiter-8 from 1959 is also very sharp wide open. Therefore, when I bought the Canon 50/1.5 I expected it to be sharper than it turned out to be.

02Pilot, I haven't made any prints yet, just compared it on screen and noticing a difference at the widest aperture that I wasn't pleased with. Purely subjective opinion 🙂.

splitimageview, thanks for the interesting link comparing your sonnar lens at f/1.5 and f/2. A striking difference that resembles the difference between those two apertures of my Canon sonnar as well. As mentioned above, two of my russian sonnars are very sharp wide open so I had higher expectations for the Canon.

goamules, thanks for your comments and images. I saw your images in another thread and you have a sharper copy than I do. I'm wondering, should I try another copy...?

darinwc, yes I agree, nively sharp from f/2 and getting better from there. I'm not sure though that my copy is "fairly sharp" at f/1.5. Big difference between wide open and f/2.

I really like this lens. The only drawback in my opinion is the wide open performance. If I really need f/1.5, then my J-3 is the better performer at that aperture. Guess I had expectations before I bought it that this would beat "the russians".
 
Ultimately condition is going to determine how well the lens performs.
The Canon lens often has haze and/or fungus. The inner cousins are very soft and can get scratched from cleaning attempts.
So if you get one, check out internally very carefully.
The sonnar, summarit, Canon 1.5, and Jupiter 8 are all similar designs.
Somewhere I found a comparison and they all performed about the same. Very small differences that could easily be variations from the build.
 
Are you sure it is in focus at f/1.5? I seem to recall Brian Sweeney commenting that his copies of the Canon were optimized for correct focus at f/2.8 and would front focus wide open.

I have noticed that my copy of the Canon 1.5 is sharp wide open but low contrast compared to same lens at f/2 so if I'm going to shoot the whole roll wide open I can agitate more vigorously in development and get that contrast back.
 
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