[UncleVanya]

Does everything really even out at f/2.8 to f/4? Or is it just that there's enough depth of field to compensate for focusing error?

I'm in a bind here now. I've got examples of the SMC Takumar 50mm/1.4 that are very sharp wide open -- albeit with razor thin depth of field -- but they are all family photos and I don't post those online. I'll have to try to find something where the thing that's in sharp focus isn't a family member's eyelashes.

My basic point is that the slower the lens, the sharper it will seem to be wide open, simply because focusing error becomes less of an issue.

I’m not disputing this happens but actual measurements suggest the f1.4 lenses are not as sharp as the f1.7 or f1.8 lenses until about f2.8 - at the SAME f stops.

[TwoUptons]

Does everything really even out at f/2.8 to f/4? Or is it just that there's enough depth of field to compensate for focusing error?

I'm in a bind here now. I've got examples of the SMC Takumar 50mm/1.4 that are very sharp wide open -- albeit with razor thin depth of field -- but they are all family photos and I don't post those online. I'll have to try to find something where the thing that's in sharp focus isn't a family member's eyelashes.

My basic point is that the slower the lens, the sharper it will seem to be wide open, simply because focusing error becomes less of an issue.

That's actually part of the point I'm not doing a good job making

I also have some really sharp photos wide open with the 50s and the 85 that I don't generally share for the same reason...
For me, most of the lack of sharpness on shots from those lenses is from my own movement as I breathe... unless I'm braced against something... it's infuriating... but not the lens' fault...

Even when I do nail focus and remain still, though, f2.0, for example, is sharper on my F50 f1.7 or M50 f1.7 than on either the A50 f1.4 or the Super-Tak 50 f1.4, but all four of those are better than my M50 f2.0. And all of the lenses will sharpen up overall with smaller apertures up to at least f5.6/f8, independent of the depth of field, especially away from the center.

It's not that the f1.4 lenses aren't sharp, but rather that the others are just a touch sharper at the same aperture up to about f2.8 or f4.0.

Oh, and my Super-Tak has six blades... though they seem more evenly spaced than the ones on my A50 f1.4...

-Eric

[UncleVanya]

I still can’t find any direct data. This shows similar results for 1.4 vs 1.7 lenses at f2 and f1.7 respectively which is better than what I’ve seen elsewhere:

http://www.takinami.com/yoshihiko/photo/lens_test/pentax_normal.html

I guess it’s worth saying these issues are probably subtle. My own use suggests the better bokeh of the f1.4 (due to the higher number of aperture blades) is worth it.

[Ephraim]

Fascinating read, thanks very much for the comments!!
Regarding blades, does 6 vs 8 indicate only the shape of the direct light balls or also the general "washing" effect?

[UncleVanya]

Fascinating read, thanks very much for the comments!!
Regarding blades, does 6 vs 8 indicate only the shape of the direct light balls or also the general "washing" effect?

Bokeh is weird. I think more than simply the number of blades is involved.

[Ephraim]

This is where I got the softness comment about the rubber-zoom ring version

https://youtu.be/sG_69I45H2k?t=489

The 1.4 image he shows there is unusable, and he's probably a better photographer than I

[c.a.m]

This is where I got the softness comment

I follow Simon's utak YouTube channel. I'd say he's a credible, trustworthy reviewer. That's a good video, which I had seen before.


- Craig

[Dartmoor Dave]

Even when I do nail focus and remain still, though, f2.0, for example, is sharper on my F50 f1.7 or M50 f1.7 than on either the A50 f1.4 or the Super-Tak 50 f1.4, but all four of those are better than my M50 f2.0. And all of the lenses will sharpen up overall with smaller apertures up to at least f5.6/f8, independent of the depth of field, especially away from the center.

Ah, I think I understand your point now and of course what you're saying is true with the lenses stopped down a bit. Focusing error is less likely to be a factor and actual sharpness will be more relevant (when I talk about focusing error and actual sharpness I'm talking about real world use rather than on a test bench).

I was just fixated on what was said in the original post:

I heard that the rubber zoom Tak is unusable at 1.4 because it's way too soft

On this point, I still maintain that anyone who thinks that the Tak 50mm/1.4 is unusably soft wide open is simply missing focus -- either that or entertaining impossible hopes of sharpness right across the frame, rather than just in the centre where it matters. I've lost count of how many reviews I've seen of fast manual lenses in which the reviewer calls it unusably soft wide open, when it's obvious from their sample photos that they just can't focus the darn thing properly.

And of course, one person's "unusably soft" lens can easily be another person's "fine for my own needs".

[GUB]

This is where I got the softness comment about the rubber-zoom ring version

https://youtu.be/sG_69I45H2k?t=489

The 1.4 image he shows there is unusable, and he's probably a better photographer than I

The video opened at about 12.00 and I watched like 30 secs of it but the padlock example showed classic dof softness and a little softness from being slightly overexposed. The S and the L are both oof on each side of the focal plane.
The takinami tests show how similar the whole lot are.

[hjoseph7]

I don't know about the 50mm f1.7 but the SMC lenses can be used with older cameras's such as the Spotmatic without having to stop down...

[pres589]

I don't think a single "sharpness test" can really determine these sorts of things. I believe that the f1.4's are okay-sharp wide open but light sources in the frame will look pretty blown out and soft, moreso than with the 1.7's. Think streetlights at night. I say I believe this because I don't know this, I haven't done back to back testing to prove out any of it. Then there's also edge sharpness of non-illuminated objects, like the edge of a physical item or something like newsprint. Newsprint is good because depth of field isn't going to mess with things like has been mentioned already in this thread.


I really like the M 50 1.7. One of my favorite lenses for my k-mount cameras. Here's a picture I took with my copy, on Tri-X 400 and pushed in development. Shot wide open. I have no complaints about wide-open sharpness with this lens.

[Sjak]

So I have an opportunity to purchase a mint, 50mm 1.4 Takumar SMC Rubber Zoom Ring for about 50$ without any marks.
I already have my much loved and much used 1.7 Pentax-M.

I heard that the rubber zoom Tak is unusable at 1.4 because it's way too soft, making such a purchase a lateral move rather than an upgrade?

Unusable for what? I've had various classic 50 1.4s over the years, and I would certainly not call any unusable at f/1.4. However, it takes some practice to use f/1.4 effectively and creatively.

But it depends on your application of course.

How do you anticipate using the f/1.4? There are situations where the half stop makes a nice aesthetic difference. If you're planning to shoot at f/4-f/8 most of the time, and you're happy with your current lens, then I would not bother with adding a 1.4. The M 50 1.7 is a great lens, actually one of my favorites, and affordable as it was one of the "kit lenses".

Maybe you could simply get the 1.4, see if you like it, and if not, sell it again. On average, classic fast 50ies have increased in value over time in recent years, so there's little financial risk, and maybe even an opportunity to make a few euros profit

[Jonathan Mac]

I see this has really kicked off...

For my part, having used several copies of both (though the Takumars were the older knurled focus ring type), the M 50mm f/1.7 is certainly my favourite of the two. It's smaller, cheaper, optically better and just as pleasant in use as the Takumar 50/1.4. Sharpness wide open (though this is a different f-value for each) is very similar and both are usable wide open if focus is dead on. The bokeh of the M is superior (much smoother and without the ugly granularity of the Tak), despite having fewer aperture blades (number of which is far from being the be-all-end-all of bokeh). At f/2.8 and beyond in terms of image quality there will be very little difference.

If you want a nice Takumar fast normal prime then the 55mm f/1.8 (or f/2) is superior to the 50/1.4 in all but raw speed.

For $50 though, I don't think you would lose any money if you sell it on later, so by all means give it a go and decide for yourself.

[Dartmoor Dave]

If you want a nice Takumar fast normal prime then the 55mm f/1.8 (or f/2) is superior to the 50/1.4 in all but raw speed.

I completely agree. The 55mm/1.8 is better than the 50mm/1.4 in everything except that little bit of speed. In fact, I think the 55mm/1.8 is better than the 50mm/1.7 too. At one time I owned all three of those lenses and the 55mm was the one I almost always went for.

It's strange: I ended up defending the 50mm/1.4's reputation in this thread, even though actually I think it's one of the most over-rated lenses out there.

[GUB]

I completely agree. The 55mm/1.8 is better than the 50mm/1.4 in everything except that little bit of speed. In fact, I think the 55mm/1.8 is better than the 50mm/1.7 too. At one time I owned all three of those lenses and the 55mm was the one I almost always went for.

It's strange: I ended up defending the 50mm/1.4's reputation in this thread, even though actually I think it's one of the most over-rated lenses out there.

The only thing I take issue with is the word "better". There is a difference between the 50s and the 55s. I tend to think the 55s have a more creamy neutral bokeh and the 50s have a slightly more flamboyant bokeh. A highly subjective opinion which means I tend to reach for the 50s . But that doesn't make them better!.