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05-01-2011, 05:01 PM   #1
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A135mm wide open - nice!

Went out yesterday to take some shots at f2.8 (to practice my manual focusing skills). ALL the following photos are taken at f2.8.

Here are some results, all taken on board the ferry from Circular Quay to Watsons Bay, which we actually boarded by accident (we wanted to go to Cockatoo Island). My fault - I rushed onto the ferry in my excitement and didn't bother checking.

There were a few other photographers on the ferry doing the same thing as me:






My friend Tim (his wife Kimberley is actually the photographer, he's using her "backup" camera):


I quite like this photo:


But on this one you can see the reflection of other people on the ferry in her sunglasses:


Just to show how crazy thin the DOF is at f2.8, I focused on the woman on the right, but her friend next to her is out of focus:


Obligatory Sydney Harbour photos:












And lastly, I thought this was kinda cute:



Last edited by Christine Tham; 05-04-2011 at 04:44 PM.
05-01-2011, 09:57 PM   #2
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Your DA* 50-135 isn't sharp at 2.8? Odd. I mean, very few lenses don't increase in sharpness as you stop them down a stop or two, but from all the reports (and my own instance) the 50-135 is very sharp @ 2.8. Of course, I wouldn't expect it to be as sharp as a prime, but compared to other zooms, my 50-135 is a razor.
05-01-2011, 10:17 PM   #3
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QuoteOriginally posted by jstevewhite Quote
Your DA* 50-135 isn't sharp at 2.8? Odd. I mean, very few lenses don't increase in sharpness as you stop them down a stop or two, but from all the reports (and my own instance) the 50-135 is very sharp @ 2.8. Of course, I wouldn't expect it to be as sharp as a prime, but compared to other zooms, my 50-135 is a razor.
Yeah it's much sharper than any other zoom I've owned, and in fact it's only zoom I still use on a regular basis (my Sigma 18-50/2.8 EX DC is now semi-retired).

But wide open, I wouldn't say it's razor sharp (I will say it's razor sharp from f5.6 onwards). The A135mm is much better than it, I can see incredible detail right down to the last pixel.

I'm now pretty much exclusively shoot on primes, and have done so for the last few years. The 50-135 is a compromise lens that I take when I only want to take one lens and nothing else.
05-02-2011, 08:23 AM   #4
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QuoteOriginally posted by Christine Tham Quote
Yeah it's much sharper than any other zoom I've owned, and in fact it's only zoom I still use on a regular basis (my Sigma 18-50/2.8 EX DC is now semi-retired).

But wide open, I wouldn't say it's razor sharp (I will say it's razor sharp from f5.6 onwards). The A135mm is much better than it, I can see incredible detail right down to the last pixel.

I'm now pretty much exclusively shoot on primes, and have done so for the last few years. The 50-135 is a compromise lens that I take when I only want to take one lens and nothing else.
Ah, ok, that makes more sense. Yeah, the 50-135 isn't as sharp as, say, my Tamron 180 f2.5, or my 100mm f2.8 Macro ( but what is, right? ). Thanks for clearing that up; I was about to tell you that you should get it fixed.

05-02-2011, 09:36 AM   #5
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Would be interesting to see side by side 100% crops (identical scene & exposure) comparing the two at f/2.8. The 50-135 is generally considered one of the best of the zooms of its range; the A135/2.8 one of the worst primes of its focal length. Generally speaking, sure, you expect a prime to outperform a zoom, but if there going to be a counterexample, I'd expect this to be one of them.
05-02-2011, 02:07 PM   #6
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This is a link of my various primes all shooting the same scene (teddy bear and friends) at various apertures:
Pentax primes lens sharpness test - Windows Live

And this is the DA*50-135 capturing the same scene at various apertures and focal length:
DA50-135 focus - Windows Live

These are all full resolution JPEGS, so you can zoom in. If you get a browser error when you click the link, hit refresh - for some reason the page takes a while to load (probably because Windows Live is dynamically trying to resize the full size pictures).

The DA*50-135 is very sharp from f5.6 onwards - comparable to some of the primes, but looks distinctly soft at f2.8.
05-02-2011, 02:45 PM   #7
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QuoteOriginally posted by Christine Tham Quote
This is a link of my various primes all shooting the same scene (teddy bear and friends) at various apertures:
Pentax primes lens sharpness test - Windows Live

And this is the DA*50-135 capturing the same scene at various apertures and focal length:
DA50-135 focus - Windows Live

These are all full resolution JPEGS, so you can zoom in. If you get a browser error when you click the link, hit refresh - for some reason the page takes a while to load (probably because Windows Live is dynamically trying to resize the full size pictures).

The DA*50-135 is very sharp from f5.6 onwards - comparable to some of the primes, but looks distinctly soft at f2.8.
Huh. Mine doesn't look like that. Hard to say, but it looks like some motion blur or front focus. The lens is well known for being sharp from wide open (at least in the center); perhaps yours front-focuses (and stopping down brings the target into the DOF) or is defective in some manner?

see Pentax SMC-DA* 50-135mm f/2.8 ED [IF] SDM - Review / Test Report - Analysis
05-02-2011, 02:54 PM   #8
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QuoteOriginally posted by jstevewhite Quote
Hard to say, but it looks like some motion blur or front focus.
Camera was on a tripod, 2sec delay to eliminate mirror flick.

The scene was focused manually using Live View, and then focus locked for all apertures. The specific focus point for all the shots was the fur just below the bear's nose.

If you doubt my manual focusing skills, there is no reason why all the primes look sharp wide open but the DA* doesn't.

And I tried with a second DA* supplied by Pentax Australia and achieved the same results.

I even took several versions of the DA* shots to absolutely convince myself I was not doing something wrong.

It's easy to say "My shots don't look like that" but unless you are shooting exactly the same scene in exactly the same conditions it's hard to tell. I have shots from the DA* that seemed sharp to me when I took them, but now that I know the lens is soft wide open, I go back to them and I can see the same tell tale signs of softness, but often the subject matter can affect perception of softness.


Last edited by Christine Tham; 05-02-2011 at 03:00 PM.
05-02-2011, 03:06 PM   #9
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QuoteOriginally posted by Christine Tham Quote
Camera was on a tripod, 2sec delay to eliminate mirror flick.

The scene was focused manually using Live View, and then focus locked for all apertures. The specific focus point for all the shots was the fur just below the bear's nose.

If you doubt my manual focusing skills, there is no reason why all the primes look sharp wide open but the DA* doesn't.

And I tried with a second DA* supplied by Pentax Australia and achieved the same results.
LOL! Not making any accusations! Just saying, I (and many others) have had much different experience with the lens. I'm sorry you've not had better luck; it's a very expensive lens to be unhappy with!
05-02-2011, 03:19 PM   #10
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Something looks horribly wrong with the 50-135 in the 135/2.8 shot, as any number of samples from others show the lens is capable of far better results. Judging by the shape of the specular highlights, I'm going with camera shake. They are pretty obviously tracing a circular outline. Similar story with the f/4 sample, except in that case, the pattern of the camera shake is not circular but linear. Definitely worth repeating that test in better light before writing that lens off. The only thing I'd conclude from that test is that your tripod isn't worth much.
05-02-2011, 04:06 PM   #11
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QuoteOriginally posted by Marc Sabatella Quote
The only thing I'd conclude from that test is that your tripod isn't worth much.
If that was true, then the primes would have been also blurry.

Also, I deliberately included photos in that gallery taken at 1/750 and 1/1000 second that are also soft. Are you suggesting camera shake for those as well?

Anyway, this is a rehash of an earlier thread where plenty of other people (including Adam) have chimed in to say those photos are normal for the lens.
05-02-2011, 04:16 PM   #12
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QuoteOriginally posted by jstevewhite Quote
I'm sorry you've not had better luck; it's a very expensive lens to be unhappy with!
Oh, I'm not unhappy with it - have taken lots of good photos with it. But it's good to understand what it's limitations are. Remember these photos are taken at medium JPEG quality setting, no additional processing. They will look better with some post-processing.

At the end of the day, every lens has it's own quirks. The A135mm for example has a bit of CA and suffers from purple fringing a fair bit in strong light. The bokeh is nowhere near as good as the DA* - the 50-135mm has amazing creamy bokeh.

Accept the limitations, and take advantage of them if possible. I think the DA* will make a great portrait lens wide open - that slight soft look will enhance the face coupled with the bokeh.
05-02-2011, 04:16 PM   #13
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QuoteOriginally posted by Marc Sabatella Quote
Something looks horribly wrong with the 50-135 in the 135/2.8 shot, as any number of samples from others show the lens is capable of far better results. Judging by the shape of the specular highlights, I'm going with camera shake...
I see something different: the same type of aberration I get from the Cosina 55mm f1.2 wide open, and an old Vivitar 24mm f2. An example I have on line shows it:



A string of Christmas lights on a dark background (pretty much what my example photo is) will show this clearly. And under ordinary conditions, it just looks "soft".

I've been in the same room as a DA* 50-135 but don't own one.
05-02-2011, 04:26 PM   #14
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QuoteOriginally posted by Christine Tham Quote
The DA*50-135 is very sharp from f5.6 onwards - comparable to some of the primes, but looks distinctly soft at f2.8.
To say that a DA*50-135 is distinctively soft at 2.8, is a pretty bad generalization. I am very happy with the sharpness wide open of this lens, that it gets sharper as you stop down is but normal for any lens and is a bonus.

If you are unhappy with your copy you should get it calibrated along with your camera body.
05-02-2011, 04:33 PM   #15
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QuoteOriginally posted by selar Quote
To say that a DA*50-135 is distinctively soft at 2.8, is a pretty bad generalization. I am very happy with the sharpness wide open of this lens, that it gets sharper as you stop down is but normal for any lens and is a bonus.

If you are unhappy with your copy you should get it calibrated along with your camera body.
I think everyone has different standards on what they will accept as sharp or soft. I don't necessarily impose my standards on others, nor am I unhappy with the lens or believe there is anything wrong with it. Other people (who I trust) have said they believe those photos are representative of the lens.
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