Body: T2i Lens: Kit, 18-55mm f3.5-5.6

I went to shoot a sunrise this morning at the beach and got some great pictures, but when I uploaded them to some light post-processing, I was slightly surprised by how unsharp it was, and the amount of noise there was when I zoomed in. Is this normal for this camera/lens? My settings for the photo attached were 1/25, f4.0, ISO 100, and focus was set on the chair. My assumption is that it has something to do with the amount of available light, but I've seen plenty of sunrise/sunset pictures that are almost impossibly sharp.


View full-size to see what I mean

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    This looks reasonably sharp to me. – fahad.hasan Jul 10 '11 at 13:51
  • Even zoomed in? Maybe it's just me... – Jon Jul 10 '11 at 14:01
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    I wouldn't expect a 100% view on a monitor to look all that sharp up close, that's expecting too much from the monitor. – John Cavan Jul 10 '11 at 14:27
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    @John Cavan, I don't understand what the monitor would have to do with it... – Ilari Kajaste Jul 10 '11 at 16:29
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    @Ilari Kajaste - if your monitor is displaying at 96 dpi it is a very coarse display (good printing is more than 3 times that density) and will look soft as a result especially at the distances we sit at. Google "pixel peeping" to see what I mean. – John Cavan Jul 10 '11 at 17:45

The Canon EF-S 18-55mm Kit lens is not the sharpest lens known, not if you're judging the pic at 100%. But when you're using smaller version of the image, sharpness is acceptable. Your example image looks sharp enough to me in this size, for a kit lens, its a good result.

Now, the noise. Its a very complicated term. It depends on a lot of things, one of them is wavelength of the light, or you can say color of the light. Blue channel is the noisiest channel and green is the least. Your sky is mostly blue and looks like that's the cause of the noise you're seeing.

You did not mention if you shoot raw or jpeg. jpeg images converted from raw provides better sharpness comparing to in camera jpeg. Also, T2i has a very powerful sensor, it's image quality increases a lot more when you use it with a superior lens. So, if you're not happy with it, try getting a lens known for its sharpness (rent for a day or ask a friend), shoot with it and check if it makes you happy or not.

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  • I did shoot in RAW, I forgot to mention that :) I know the kit lens isn't the greatest, but I figured I would ask anyhow! I've been planning on buying a nifty fifty, which, despite its affordability, produces some pretty awesome results. Thank you for your thoughts! I'm leaving this up for a little while longer to see if anyone else can offer some useful knowledge. – Jon Jul 10 '11 at 14:11
  • I can back up the assertion that the EF-S 18-55 is a very soft lens. This lens in particular has some rather severe problems with CA. While it does not always present itself as colored fringing, it does have the effect of softening edges when you think you otherwise have focus nailed. Its one of the cheapest lenses Canon makes, at around $100 or so. You can't expect much from such a lens...the only way to truly get sharper results would be to shell out some cash for a better lens. – jrista Jul 11 '11 at 2:09
  • @Jon: The 50mm f/1.8 produces tack sharp results from f/2.8 and onwards but if you use it at f/1.8, its kinds soft. Again too small aperture (normally beyond f/16) soften your images due to diffraction. – fahad.hasan Jul 11 '11 at 5:23

The sharpness seems reasonable for that lens at f/4. Noise can make an image look less sharp, but you could sharpen it a little in post.

As for the noise, it's most likely the result of underexposing the image. Underexposing an ISO100 will lead to more noise than using a higher ISO! If that weren't the case there'd be little point in having ISO settings.

The reason for this is that the camera electronics create a sort of base level of noise, regardless of how much light there is. Using a high ISO amplifies the analogue signal (which will be low in low light) before it is converted to digital and thus gives you a much better signal to noise ratio (therefore less observed noise in the image).

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  • in terms of underexposure leading to more noise, only if he raised the exposure in post right? @Jon - was the exposure raised in post processing? – rfusca Jul 10 '11 at 18:59
  • @rfusca Not necessarily - underexposure leads to a poor signal to noise ratio, and when you increase the exposure in post that doesn't change (unlike when you increase exposure by letting in more light or raising ISO). But if you don't brighten in post, the signal to noise ratio is still poor, and when you look at the image your eyes/brain will adjust the image and it will look noisy. If you want really dark images it's better to darken in post! – Matt Grum Jul 11 '11 at 13:21
  • +1 The picture is definitely underexposed. That lens has decent IS, so with some care it can be handheld for 1/4 sec at 18 mm. The picture can then be uniformly darkened in post-processing to get the intended effect of dim predawn light. – whuber Jul 11 '11 at 14:54
  • Pardon my absence...I didn't anticipate such a response post-accepting an answer. @rfusca, no post exposure adjustments were made, only a slight bump in saturation and contrast. @whuber, when can I tell if an image is properly exposed? Will the histogram tell me that? Or is it something a photographer just "knows"? – Jon Jul 11 '11 at 16:09
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    @jon it's tricky - there is no "correct" exposure, ultimately it's up to the photographer. Sometimes "underexposed" means the image captured was darker than the photographer intended, which could be an error in technique. When I said "underexposed", I meant the exposure was low, if I was going to intentionally shoot a dark moody image like the one you posted I'd increase exposure in camera and darken in post. – Matt Grum Jul 11 '11 at 16:28

That looks sharp enough for the gear and settings you used, and in general it looks sharp enough anyway. Pixel peeping is misleading as it's rare for people to actually see that kind of detail close up. Pixel level detail in photos is not quite as perfect as you might have expected.

Print this image and it will look as sharp as a tack, resize it for the web and it will sharp as a tack.

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