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Wide angle Lenses with focal lengths shorter than 14mm.

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Old 30th September 2012
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Is my 17mm f2.8 prone to poor contrast?

In my recent thread of pictures taken with the 17mm f2.8 I mentioned that the lens seemed to have poorer contrast than many other lenses. Ulfric, who has used a 17mm for much longer than me replied that his lens has plenty of contrast. So is it just my perception, or my copy of the lens? Are other users of this lens able to comment?

Here are a couple of examples to illustrate what I've noticed about the contrast of this lens:-



This first picture is an ORF resized and saved as a JPEG wih no other processing. To me the contrast looks pretty low and makes the image very flat. The histogram is very good, indicating the need for only a tiny tweak in Levels (which I have not done), so this isn't an issue of poor exposure.

The next picture is the same Orf file but processed with a 35% increase in contrast. This was the only adjustment and it has noticably improved the picture in my opinion. 35% seems a large adjustment; normally to get the look I want I increase contrast in the range of 15 to 20%, using more only if I want to use it for particular dramatic effect.

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Old 30th September 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

The second example is a little more severe. It was taken against the light (without a lens hood) and I suspect that this is responsible for much of the poor contrast. Once again it is an ORF resized and saved as a JPEG with no other processing.



And here it is with contrast increased by 40%, which seems a lot to me.



Finally, the same image with some Levels adjustment as well.




So is there a contrast issue, or am I being too critical? Is it something to be concerned about as the files seem to respond well to processing anyway?
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Old 30th September 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

Even more intriguing, why is there an obvious difference in these pictures when I view them in Windows Gallery but it becomes barely noticable when I post them on the forum? Surely the forum software doesn't apply any processing? Has anyone else noticed this peculiarity?
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Old 30th September 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

Might be interesting to see the results of a head-to- head comparison (same shot, same exposure values) with the lens mounted on both the E-P2 and E-M5. Yes, the two sensors are entirely different, but the relative lack of contrast - if it is the lens - should show up in both.

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Old 30th September 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

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Originally Posted by JohnI View Post
Might be interesting to see the results of a head-to- head comparison (same shot, same exposure values) with the lens mounted on both the E-P2 and E-M5. Yes, the two sensors are entirely different, but the relative lack of contrast - if it is the lens - should show up in both.

John
Good suggestion, John, thanks for that.
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Old 30th September 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

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Originally Posted by Zuiko View Post
Even more intriguing, why is there an obvious difference in these pictures when I view them in Windows Gallery but it becomes barely noticable when I post them on the forum? Surely the forum software doesn't apply any processing? Has anyone else noticed this peculiarity?
Well I can see the difference - I suspect that scrolling down rather than clicking between tends to obscure things a bit.

The same psychologists that allowed babies to plunge off chequered tables onto chequered floors (a test of the development of depth perception) probably have a theory to explain it.

And OK the early 1950s introduced chequed linoleum, and it was a great idea for wipe clean surfaces. But why did they leave a baby on a table unrestrained?

Sorry

Nick
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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

Quote:
Originally Posted by Nick Temple-Fry View Post
Well I can see the difference - I suspect that scrolling down rather than clicking between tends to obscure things a bit.

The same psychologists that allowed babies to plunge off chequered tables onto chequered floors (a test of the development of depth perception) probably have a theory to explain it.

And OK the early 1950s introduced chequed linoleum, and it was a great idea for wipe clean surfaces. But why did they leave a baby on a table unrestrained?

Sorry

Nick
You're right, Nick, opening another browser and clicking between images does show the difference; that's an interesting illusion when scrolling. Not sure about bouncing babies off lino, though - seems a harsh way to test perception!
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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

I really shouldn't comment as I haven't got the lens or camera.

But the first shot of the reeds looks a bit overexposed, there are areas under the facing reeds where detail has been lost in shadow, but the image still shows them as quite light. To a degree the histogram shows that with a bit of a lhs tail.

But it's a dull light image, difficult to draw a conclusion.

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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

I can't see you getting to the bottom (or even the top) of the problem without side-by side examples of the same scene taken with a lens which gives you higher contrast ... on the same body and at the same time.

Edit ;
I just had a look back at one of my lens test pages and I can detect a slightly lower contrast for my mZukio17mmF2.8 versus the Lumix14-45, which seems to be my contrast king, and other forum threads elsewhere have shown it too.
My 4/3rds 14-54MkI has exactly the same contrast as my 17mm, in my view, and that lens also has excellent contrast.
My 17mm has at least as much contrast as my collapsible mZuiko14-42 lenses.
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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

converting an ORF to JPG won't normally apply any level changes (depending on software of course), so raw files will tend to be flat compared to an OOC JPG.
Could be a combination of flat light conditions, slight over exposure etc rather than the lens.
as has been said, only true way to find out is comparison with other lenses on same shot.
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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

That gate shot seems to be suffering from some general flare: What they sometimes call non-image forming light. In the old days it would be dust or grease on the uncoated lens, and it would have been much much worse. These days we expect lenses to be near perfect and that sort of shot is a harsh test indeed.

I find the otherwise excellent 45mm f1.8 lens needs my hand held lens hood* in many circumstances to avoid this problem. I forgive it because any lens that performed perfectly under heavy backlight would be beyond my financial means

Pete

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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

Seems I've got some more controlled shooting to do if I want to get to the bottom of this. On the other hand nobody is saying that they can see a contrast problem, so it may just be me being hyper-critical based on a small number of shots. I'm certainly happy with how the shots from the day processed, which I suppose is the main thing. The bottom line is that, with a possible cautionary note regarding contrast, the 17mm performed rather better than I might have expected from it's reputation.
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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

John - have you tried other lenses on the same body? I wonder if maybe it is the body making the difference rather than the lens. Also you say that you have processed the ORF without any adjustments - I think that with some raw processors (Oly Viewer for example) they are sensitive to camera settings and will apply them by default, so perhaps you have contrast set to low on the body or something.

Sooo many variables to consider, the only way to get to the bottom of it is to change one at a time.

Ciao ... John
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Old 1st October 2012
Ulfric M Douglas Ulfric M Douglas is offline
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Re: Is my 17mm f2.8 prone to poor contrast?

I'll just keep quoting this ;
Quote:
Originally Posted by Ulfric M Douglas View Post
... side-by side examples of the same scene taken with a lens which gives you higher contrast ... on the same body and at the same time...
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Old 1st October 2012
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Re: Is my 17mm f2.8 prone to poor contrast?

Quote:
Originally Posted by Bikie John View Post
John - have you tried other lenses on the same body? I wonder if maybe it is the body making the difference rather than the lens. Also you say that you have processed the ORF without any adjustments - I think that with some raw processors (Oly Viewer for example) they are sensitive to camera settings and will apply them by default, so perhaps you have contrast set to low on the body or something.

Sooo many variables to consider, the only way to get to the bottom of it is to change one at a time.

Ciao ... John
That's a very fair point about the sensor, the E-P2 is new to me too.
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