How to get sharp pictures… pt 1
It was odd when I used to shoot with the D300, I remember comments from folks… “Wah! Very sharp”, “Fuyoh! Syap syap leh… what lens you use”…so on, so forth. So when I switched to the 5Dmk2, I was anticipating less sharpness in my final photos. However I found that my output were just as sharp if not sharper than my original D300 shots I made years back.
How was this possible? Aren’t there like 9/10 reviews on the web that says Nikon lenses are sharper than Canon’s? Is there something wrong with these reviews or are they somewhat bogus? There could be some truth in it but remember that these tests are usually done using test charts which have nothing to do with real life photography. You don’t post photos of test charts for your photography competitions right? If you did people will think you’re bonkers!
Remember that these tests are usually done on DSLR bodies. Perhaps if the tests were done on 35mm film SLR bodies with the same type of film, then some real comparisons can be done. Even that would be tricky at best. Otherwise, the comparison really is on how both Nikon & Canon handle the RAW processing & after which the Bayer interpolation, WB/Tonal adjustments & in-camera sharpening. Not very apple to apple is it? No way the makers of Nikon & Canon will program their processing to be exactly the same. It’s all a matter of interpretation & preference so perhaps the folks at Nikon prefer exaggeratedly sharp images… it really is a matter of taste.
Any lens when used properly, will always be sharp. I’m talking about even the lenses that were used back in the 1800s. Optical design has been a science much longer than photography was around. If a shot isn’t sharp, usually it has nothing to do with the lens.
In Ansel Adam‘s reply to Edward Weston’s request for lens suggestions back in June 3rd, 1937, Ansel said, “Any good modern lens is corrected for maximum definition at the larger stops. Using a small stop only increases depth…”. Ansel said to stop worrying about lens sharpness since all the ones that Edward was considering were already sharp. This was back in 1937! Today even the cheap kit lens & plastic lenses are sharp when used properly. In 2010, sharpness is the last thing you need to worry about when selecting a lens. The only way a lens is not sharp is if it were defective & that will be the only reason.
So how do you get sharp images if the problem isn’t the lens?
In this part of the article I will talk about in-camera sharpening & “using the lens properly”. The next part of the article will be about post processing sharpening.
What I did was set up a tripod near my apartment window & pointed my camera at a prefixed position framing the houses below as my subject. I used my 50mm f/1.4 for this purpose. For the first test, I took 3 shots with different in-camera sharpness settings. Then for the second test, a total of 9 shots with 9 different f-stop intervals between f/1.4 to f/22. All the images here are enlarged to 100% crop size at 72dpi resolution.
All modern-day digital cameras have built-in settings which allow you to alter the sharpness output of your jpgs one way or another. On the Canon, press the Picture Style button & press the INFO button. Select Sharpness, press the SET button & use the quick command dial to increase the sharpness setting. To set it, press SET again. By default the sharpness is at +3. See below the image comparison between +3, +5 & +7 sharpness settings. All 3 images are shot using f/5.6.
Obviously the +7 setting is the sharpest. However if you pixel peep, you will notice halos between the light & dark areas.
Sharpness is determined by two factors, resolution & acutance. Resolution is the ability to resolve fine detail. It is largely determined by the camera & lens. Acutance is the contrast between the light & dark edges in an image. The quicker the transition between the light & dark areas the sharper the edges appear to be as interpreted by our brain. Halos form when too much sharpening is done on an image. This has nothing to do with resolution, it only gives the impression that an image is sharp. This is how in-camera sharpening is done, by exaggerating the light/dark areas so that the perception of the final image is sharper.
Aperture in relation to sharpness
Generally if you stop a lens down more, you get sharper results. However if you stop down too far, diffraction occurs & you will get softer results. This is quite easy to demonstrate. If you squint your eyes a little, you will notice that things get clearer. But if you squint more, up to a point things start to get really fuzzy. This is exactly what happens in a camera lens too.
At f/1.4 & f/2.0, things look very fuzzy. At f/2.8 the image starts to get sharper right up until f/8.0 which is the sharpest aperture. At f/16 onwards you can start to see that diffraction is kicking in & causing the image to lose sharpness. Therefore the sharpest aperture on the 50mm f/1.4 is f/8.0. In fact almost all lenses have the same sharpness at f/8.0
In other words, for maximum sharpness, your choice of aperture is a lot more important than your choice of lens!!
… next, post processing sharpening…