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20mm 1.7 sharpness wide open

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agc1976

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I'm finding that my 20mm wide open while is sharp, it isn't RAZOR sharp. Is this how this lens supposed to perform?

Thinking about upgrading to the 25/1.4 and sharpness wide open would be one of the key features that I'd be looking at.

This is as sharp as I can get with the 20mm (straight unprocessed conversion from RAW in lightroom):



 
Listen, you have 1.3 over exposure. Your sample does not represent the lens
--
MFT in progress
 
agc1976 said:
I'm finding that my 20mm wide open while is sharp, it isn't RAZOR sharp. Is this how this lens supposed to perform?
Click to expand...
The fact is that all lenses are less sharp wide open than when they're stopped down by a couple of stops -- there is an optimum for sharpness that is usually between f/4 and f/8, depending on the specific lens design.

I don't see anything in the sample photo you posted that I would complain about. You may be wasting your money to buy another lens.

--
Darrell
 
There is nothing to complain about in this photo. The other poster who told you that you lost sharpness because you set EC to 1.3 is compleltely off base. There is nothing wrong with the histogram in this JPEG -- EC and sharpness are not closely related.

The other poster who told you that all lenses have a sweet spot is on the mark. The smaller apertures (large f-numbers) also produce worse results than the sweet spot.

In fact, dpreview has interactive lens graphs you can examine. You can specify the aperture and you can see the number of lines/mm resolution.. It is a quick way to learn about your lens' characteristics.
 
Why such a big one?
--
MFT in progress
 
Thanks for the useful replies. I get considerably sharper results from the Oly 12/2 and wanted to confirm that this was the typical result to be expected from the 20. I read somewhere that the 20 was supposed to be sharper than the 12 but this has not been the case with my samples. The 12mm is more than twice the price of the 20 so I'm happy that it is sharper.

Here's one with the 12mm for comparison (again, dicrect unprocessed RAW conversion):



 
both your photos look very very similar in sharpness. Not sure what you think you are seeing?

12mm costs $800, 20mm costs $350 used.

Seems like a waste of money if sharpness is your goal...field of view..thats a diff story.
 
jimboyvr said:
both your photos look very very similar in sharpness. Not sure what you think you are seeing?

12mm costs $800, 20mm costs $350 used.

Seems like a waste of money if sharpness is your goal...field of view..thats a diff story.
Click to expand...
Look at the eyes of the baby. Big difference. You must click on "original" to view the full size.

12mm I got because of the field of view of course.
 
I think the 20mm is remarkably sharp wide open. The 25mm may be a bit sharper in the center but I doubt the difference would be noticeable. Also, from samples I've seen at DPReview the 20mm is shaper at the edges wide open. I certainly wouldn't spend the money on the 25mm for improved sharpness over the 20mm.
 
I don't know which lens is sharper. I do know that typically depth of field is thin wide open and it is pretty tough to nail it with a kid bouncing in a pool. If you look along the child's sleeve, you can see where the focus is sharp. I'm saying, I think you just missed it in the pool but nailed it on the porch. The problem is not the lens, but the difficulty in hitting perfect focus in a dynamic situation.

Stopping down does improve sharpness, but it also expands the DOF. Wide open apertures are good for low light situations and subject isolation. Stopping down makes you life easier as long as you have the light.

BTW, cute kid. Take lots of photos.
agc1976 said:
Look at the eyes of the baby. Big difference. You must click on "original" to view the full size.

12mm I got because of the field of view of course.
Click to expand...
 
Agreed with the try shooting pool without over exposure etc but the point is ALL lenses will then not be performing as well as they could fully open.....
--
'The decisive moment'....
Always appears to happens when I'm not looking !!!!!

E-30 12-60 SW, 40-150 f3.5, FL-36R . EP-3 14-42 II plus 20 mm 1.7

http://www.picnic4you.co.uk

Pic-nic4u :-)



extension.
 
agc1976 said:
I'm finding that my 20mm wide open while is sharp, it isn't RAZOR sharp. Is this how this lens supposed to perform?

Thinking about upgrading to the 25/1.4 and sharpness wide open would be one of the key features that I'd be looking at.

This is as sharp as I can get with the 20mm (straight unprocessed conversion from RAW in lightroom):
Click to expand...
I've been using the 20mm lens for two years on my G1, with superb results at wide open, including 19"x13" prize winning prints.

Looking at your image, I notice that it is 1600 x1200 pixels - did you take it at that resolution, or have you compressed from the RAW?

I would want to see a 4000x3000 (or section thereof) before I comment on the lens itself, and not the compression or pixel lumping technique used.

Based on what I do see I would say, your exposure is fine (and doesn't affect the sharpness parameter) but I think your focus may be a fraction in front of your daughter's face. I seem to see slightly more sharpness in her right hand (but also the zip under her chin is sharpish, and I wonder if you planted the focus on her nose, so it's between the two eyes (as the further eyelash isn't that far off either).

I could be imagining this, but as that right hand has some blue and pink compression-like artifacts, such comments are probabaly invalid.

Mike
--
Mike Davis
Photographing the public for over 50 years
http://www.flickr.com/photos/watchman
 
agc1976 said:
I'm finding that my 20mm wide open while is sharp, it isn't RAZOR sharp. Is this how this lens supposed to perform?

Thinking about upgrading to the 25/1.4 and sharpness wide open would be one of the key features that I'd be looking at.
Click to expand...
According to all tests I know about the 25/1.4 is not sharper wide open than the 20/1.7. In the center, they are about the same. At the edges, the 20 is sharper.
agc1976 said:
This is as sharp as I can get with the 20mm (straight unprocessed conversion from RAW in lightroom):
Click to expand...
Pictures like the one you posted for the comparison between the 12 and the 20 are pretty useless as sharpness tests. To really test the lenses, you need to put the camera on a tripod, use self-timer or a cable release, shoot a perfectly flat and perfectly static target, make sure the camera is perfectly parallell to the target in all dimensions, and and adjust the focus meticulously.
 
The 20mm is fine at f1.7, but benefits from being stopped down to f2, which is what I usually shoot at with it.
 
Your 12 appears sharper mostly because of wider depth of field. In the first pic - it's quite sharp. Look a the hairs - If you missed the eye, especially the rear one, it's your focusing. not sharpness.

I've yet to see an equivalent setup that's as sharp wide open. Even on my 5d when stopping down a little with my 50s I don't get as sharp.

I assume you used the touchscreen and tapped on the head? If so, that can easily explain the difference in focus location. In the first instance, shallower dof, and focus is on the near ear/hair. In the second instance, focus is on the face and there's more dof.
agc1976 said:
jimboyvr said:
both your photos look very very similar in sharpness. Not sure what you think you are seeing?

12mm costs $800, 20mm costs $350 used.

Seems like a waste of money if sharpness is your goal...field of view..thats a diff story.
Click to expand...
Look at the eyes of the baby. Big difference. You must click on "original" to view the full size.

12mm I got because of the field of view of course.
Click to expand...
 
agc1976 said:
I'm finding that my 20mm wide open while is sharp, it isn't RAZOR sharp. Is this how this lens supposed to perform?

Thinking about upgrading to the 25/1.4 and sharpness wide open would be one of the key features that I'd be looking at.

This is as sharp as I can get with the 20mm (straight unprocessed conversion from RAW in lightroom):



Click to expand...
 
I don't think this photo is over exposed. My only nitpick is the bokeh of the light through the trees at the top of the frame.

The Panny 20mm falls prey to oblong pinprick, out of focus highlights which can be ugly and distracting.
agc1976 said:
This is as sharp as I can get with the 20mm (straight unprocessed conversion from RAW in lightroom):



Click to expand...
 
The 25mm F0.95 Nokton has the best center sharpness @ F2.0, F2.8 and F4.0 of the three standard m4/3rd 20-25mm lenses.

http://www.lenstip.com/lenses_reviews.html

20mm F1.7:



25mm F0.95 Nokton :



25mm F1.4 Panasonic Leica DG SUMMILUX :

 
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