To my eyes, when a Nikon Lens ISO Chart is sharp it looks like it has been (over?) sharpened. They just look unnaturally sharp.
To my eyes, when a Nikon Lens ISO Chart is sharp it looks like it has been (over?) sharpened. They just look unnaturally sharp.
Whilst I generally try not to spend too much time comparing specs and charts, I did do a quick comparison between the Canon 17-55 2.8 (which I aquired recently)and the Nikon version on the ISO charts.
Makesthe Canon lenslook prettysoft in comparison.
I am still constantly amazed by the quality of of shots frommy Canon 17-55 though []
Originally Posted by jake66
Do keep in mind that Nikon doesn't exactly have EF-S lenses. Even though their DX lenses - like the 17-55mm f/2.8 - only cover a 1.5x image circle, they still work on full-frame cameras (albeit with significant vignetting). Bryan's test of the Nikon 17-55mm is on a DX3 - a FF camera body, whereas Bryan's test of the Canon 17-55mm is on a 50D (1.6x crop sensor), since EF-S lenses only work on crop bodies.
I'm also glad that Bryan in including the comparison between the Nikon and Canon gear...but I'm a bit perplexed by exactly what you're looking at to draw a conclusion that xx canon lens is sharper than yy nikon lens.
Let me explain a bit more:
I pulled down the Canon 17-40L zoom at 17 mm and f4.0 and compared it to the Nikon17-55mm f2.8 if-ed af-s DX n lens set to 17 mm and f 4. Now that the lenses are set at the same f number and focal length, I would expect that the field of view should be identical for a valid comparison. Instead the Canon image is 50% larger than the Nikon image. Thus, I can't make a valid comparison of the two lenses! I would naturally expect the less expanded view of the resolution target to look sharper.
I understand that the two camera bodies may be at different pixel densities...but for a proper comparison, one camera (?canon?) should be down sampled, or the other camera (?nikon?) should be up sampled so that the same area of the target is compared.
Bryan in his explanation states:
<p style="padding-left: 120px;"]Why Do the Pattern Sizes Vary
While I go to great lengths to get perfect test shots, there may be very
slight variations in the framing of the tests (usually not more than a
few pixels).
I do not think these variances are enough to sway any comparisons -
otherwise I reshoot the test.
Still, some graphics in the test crops vary in size.
What you are probably seeing is lens distortion.
<p style="padding-left: 120px;"]
Perhaps someone could write a quick paragraph as how to properly use the resolution charts to augment what Bryan has already written...particularly when the field of view changes so drastically.
It would be a great help to us newbies!
I think the point is that you cannot draw such comparisons using these charts. If you look through the Canon lenses, you'll find some shot with both FF and 1.6x crop bodies, and the apparent fields of view are quite different. If you read elsewhere in the About ISO 12233 Charts page:
Most of the Canon lenses are shot with a 1DsIII body, so they can be compared to one another. Bryan indicated two lenses which have been tested with many (Canon) bodies, so you can compare the bodies. I think all of the Nikon lenses are tested with a D3x - meaning that you can fairly compare those Nikon lenses only with one another, and not with Canon lenses.
At least, that's how I interpret it.
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