Difference in picture sharpness between Canon and Nikon?

Question

My wife has a Canon 40D with a Sigma 17-70 DC (no image stabilizer) lens. She sometimes goes on shooting trips with a friend of hers who has a Nikon D90 and a AF NIKKOR 35mm f/2D (fixed focal) lens.

When taking a similar picture, using similar exposure settings and image quality, she notices the following differences:

• she prefers the colors in the picture taken with the Canon (more "real")
• the image taken with the Nikon is much sharper than the one taken with the Canon.

Just to confirm this impression, we borrowed a Canon 500D (with a Canon EF-S 18-135mm lens) and compared pictures taken with the 40D vs 500D, using the Sigma and the Canon lens on both bodies. The Sigma lens (on either body) was slightly sharper than the Canon lens, but both are way below the Nikon!

Also, having looked at pictures taken with another friend's Nikon D90 (unknown lens), his pictures again looked much shaper than similar ones taken with her Canon.

So I have the following questions:

• is there a known difference in image sharpness between Nikon and Canon?
• could this be due to the post-processing algorithm?
• what can be done to achieve similar sharpness with a Canon body?
• would switching to a fixed-focal lens improve the situation?

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Update: all pictures were taken using a tripod, and she has been using RAW format.

Answer 1

Without a doubt the fact that you're using a prime lens (fixed focal length) on the nikon is causing the difference in sharpness, especially if you're comparing it to the Canon 18-135 kit lens or Sigma 17-70 DC. Not that those are horrible lenses but the gulf in sharpness between them and the NIKKOR 35mm f2 fixed would be very wide.

I'm assuming you're performing these tests somewhere wider than f8, presumably around f8 the difference in sharpness would (mostly) go away. As you suggest, trying out a prime lens on the canon (or a kit zoom on the Nikon) would level out the playing field.

Answer 2

The sharpness differences are probably due to the lenses, not the cameras.

In general, you will find that prime lenses are sharper than zoom lenses, and lenses with short zoom ranges are sharper than lenses with long zoom ranges. So I'm not surprised that the borrowed 7.5x zoom lens is not as sharp as your 4x zoom lens, which in turn is not as sharp as the prime. Lenses also tend to be sharpest when they are stopped down a stop or two from their maximum aperture. So comparing the 35/2 at f/2.8 to the 17-70 at f/2.8 would probably give an added advantage to the 35/2.

You should look up reviews of those 3 lenses online to see how someone else has rated them. Of course it would be best if you could find a site that lists all 3 lenses, so you get a consistent viewpoint, instead of having different reviewers with different techniques.

Also, more expensive lenses typically perform better than cheaper lenses. So if you want a sharp picture, prepare to spend a lot more money. Sharp primes cost as much as not-as-sharp zooms, and the really sharp zooms cost even more. The notable exception, I've heard, is the Canon 50/1.8, which is just over $100, and everyone raves about its sharpness (I haven't used it, myself). It's not as wide as the Nikon 35/2, so it would be tough for you to make direct comparisons between the two, but it would be a relatively inexpensive way for you to get sharper pictures, as well as allow you to take pictures in lower light (e.g. indoors).

There's also the possibility that difference is sharpness is due to camera shake, which is causing blurrier photos. If you want to do a good comparison, you should mount the cameras on a tripod and use a remote shutter release. Otherwise, your camera-holding technique could be influencing the results.

You can get Nikon-to-Canon adapters, which would allow you to mount the Nikon 35/2 on your Canon; they run for between $10 and $40 on eBay, and if you don't mind focusing and setting exposure manually (you would lose the auto focus, and have to shoot in Av or M mode), it would be a cheap way for you to try out that lens with your camera.

I've read that Nikon's philosophy is to have different lenses show colors slightly differently, so you choose a lens partially for how it will capture the scene, while Canon's philosophy is to have all the lenses capture colors about the same and do any color adjustment in-camera. I don't know if that's still true, but here's a link that I used to learn how to change color settings in my Canon 30D; I assume there are similar settings in your 40D: http://www.kenrockwell.com/canon/30d/menus.htm#picture.

Answer 3

As others have noted the difference in lenses would matter quite a bit in this case.

However it's also the case that Canon cameras have stronger AA filters in front of the sensors, which blurs images a little more. Also they are more prone (and this is subjective) to applying noise reduction liberally, which can also reduce sharpness.

But again, you'd really have to get a lens that had similar sharpness to do a proper comparison, Sigma makes really nice 30mm f/1.4 and 50mm f/1.4 & f/2.8 (macro) lenses, or I think Canon also has a nice cheap 50mm - but on today's DSLR's with cropped sensors, the 30mm is more of a "classic" view.

Answer 4

This is a hard one to answer because there's so many variables: in addition to the different bodies, you are using different lenses and likely have different handholding technique.

Assuming you are shooting JPEG, my guess would be that the Nikon is using more aggressive sharpening.

Short answer, no, there's no real difference in sharpness between similar-generation Nikon and Canon bodies. Any difference you're seeing is attributable to lenses, technique, or processing. So those would be the things to look into.

Answer 5

The answer to your question about differences in sharpness, between the Canon and Nikon cameras, can be found in dpreview.com's test results.

For the Canon 40D
2100 LPH Horizontal
1800 LPH Vertical

For the Nikon D90
2200 LPH Horizontal
2150 LPH Vertical

It is true that the Nikon has marginally better sharpness, in this case, but the differences are small enough that you are very unlikely to see any difference.
The tests were conducted with the best available prime lens in both cases, effectively eliminating the effect of lens quality..

Answer 6

Aside from everything already said, and assuming you can put the same lens on both cameras, you have to be sure that the in-camera settings on both bodies are the same; i.e., sharpening, noise reduction, etc.

It is likely that this is, in practice, not possible — even when all are set to zero. You need to dig in to the menus on both cameras and set things as near as the options permit to be the same.

Having been through the Canon vs Nikon for sharpness debate and having bought both systems to do this, I think there is actually little difference!

Answer 7

As mentioned above, the largest difference is prime vs zoom. Beyond that (and the million other variables) is processing.

If they are both shot in RAW, then they are going to be processed by two different people with different styles. If you are shooting in raw and doing minimal processing and the other is shooting in JPEG then yeah, you're going to see a difference there too.

if you really want to compare, you'd have to use the same lens (i.e. a sigma 50mm with canon mount and one with nikon mount) shoot raw and duplicate the post processing so that everything is the same. But at that point your particular lens, sensor, tripod, wind, cosmic radiation will have more effect than canon vs nikon.

In short, if you're comparing apples to cucumbers. Those of us who make a significant portion or all of our income from photography don't sit around talking about the sharpness of one body or another, we're to busy arguing over other stuff.

btw, I shoot canon.