Commons:Photography critiques/July 2012

July 2012

Lucilia sericata on doorknob

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Although we already have many photos of Lucilia sericata, this one kind of fell into my lap and visited me in my room. I think it's interesting because we have no other indoor photos of them. However I'm still fairly new to macro shooting and the full-frame format, so I'd appreciate any advice on the technical side of things. I wanted to avoid focus stacking in this case (mostly to avoid stacking artifacts) so I cranked up the f number, but in retrospect I may have lost some sharpness in doing so. Thoughts? Dcoetzee (talk) 08:40, 30 July 2012 (UTC)

When you crank the aperture down to f/32 as you have done here, your resolution will be limited by diffraction, see Depth of field. There is an optimal aperture, which depends much on the lens, the distance your are shooting at, the zoom, etc. Rather complicated actually. But the optimal f number normally lies in the range 8-22 depending on the specifics. Moreover, when you pick such a small aperture the exposure time goes up. Here it is 1/60 s, and at this time scale a critter normally moves around giving rise to motion blur. Better to use a little larger aperture such that you can either lower the time of exposure or lower the ISO to get lower noise, or have enough natural light to avoid using a flash. Unless you are using a tripod, you may also have difficulties stabilizing the image at this time scale even with an image stabilizing lens. You may want to experiment photographing a small static object with the same depth as the fly, and photographs using different apertures while the camera still. If you inspect the series of images afterwards in full res you will find an optimal aperture, which balances a large depth of field with minimum diffraction blur. For other situations the optimal f-number may be different. --Slaunger (talk) 09:17, 30 July 2012 (UTC)

Optimal aperture is usually between f/8 and f/11 for sharpness, but the problem is that the DOF at 1:1 magnification at those apertures is incredibly narrow, so I had to either crank it up or resort to focus stacking (my experience with focus stacking is I tend to get some better sharpness but some unpleasant artifacts). Also my shutter time is irrelevant in this case, because I was using bright direct flash for lighting and flash duration is about 1/1000th sec (I later took some pics at 1/320 and they were basically identical). Additionally I was using a tripod with shutter delay, and the fly was remaining completely still. I did take some other pics using available light and long exposures (30 sec or so) but I didn't like how they turned out as much - the eyes were not as bright and clear. Dcoetzee (talk) 10:41, 30 July 2012 (UTC)

Yeah, it is a tradeoff. I think somewhere between f/11 and f/32 would have been better due to the very shallow DOF at 1:1. You could soften harsh flash light by diffusing the light by indirect lighning, e.g., on a piece of white paper or a shoot-through umbrella. A recent example of very good (outdoor) light achieved this way is seen and discussed here. --Slaunger (talk) 12:20, 30 July 2012 (UTC)

I experimented with bounce flash, a small softbox, and a slip on diffuser, but at the aperture I was using none of these seemed to provide enough light for correct exposure, at least at ISO 100. I didn't want to do a long exposure with flash because available light was a lamp, very different color from the flash. Maybe my SB600 is just a little weak and a more powerful studio strobe flash could've pulled it off. Thanks for the link. :-) I should've thought to try some off-camera flash shots just to play with the angle. Dcoetzee (talk) 13:31, 30 July 2012 (UTC)

April 2012

Georgian bracelet

bracelet

I was wondering what people thought of this? Jonathan Cardy (talk) 15:19, 24 April 2012 (UTC)

There is a lot of noise. The EXIF disappeared. What's your camera? Yann (talk) 15:25, 24 April 2012 (UTC)

I used a casio exilim 10 megapixel and cropped the image with Gwenview. Jonathan Cardy (talk) 16:01, 24 April 2012 (UTC)

OK. The image quality is limited by your camera capabilities. Yann (talk) 17:48, 24 April 2012 (UTC)

Photo is OK as long as you don't zoom in. Then, some colour noise in the background is visible and the object itself is unsharp or has artifacts (JPG-artifacts?). If you upload jpg-files, better without (or almost without) jpg-compression (jpg quality = 100%). In my opinion, it does not meet the formal critera to become a Quality Image, but it is not a bad photo, so why not use it for an article, if no better image is available? -- Norbert Nagel (talk) 17:51, 24 April 2012 (UTC)

I don’t know what Gwenview does, but you can crop (and also rotate and pixelize parts) JPEG images losslessly with special software with some limitations: Help:JPEG#Editing_JPEGs.

Gapado Scenary

A scenary taken on Gapado, the second-most southern Island of Korea. You can see Jeju Island on far.

This is my own work and was edited contrast of the upper(far) part. But I need a feedback which one(original version and this) is better. I want to know what is needed to become a quality image. Please let me know any kind of thought about this picture. --Naturehead (talk) 07:59, 24 April 2012 (UTC) Updated file with better quality(improved resolution). No zoom performed and just found larger source. Welcome any suggestions or opinions. Thanks. --Naturehead (talk) 15:31, 30 April 2012 (UTC)

• Could be improved if the vignetting in the top corners was removed. Also, looks a bit too vibrant. Otherwise, a nice photo! Danrok (talk) 17:31, 15 July 2012 (UTC)