Canon 50D doesn't seem sharp

[William W]

Hi Ted,

And, for completeness, my test shot was pulled at 1/25th second.

Depending upon the lens; the Tripod & Head; and the Counter Weight and/or Dampening (if used) - when using Tv (shutter speed) around 1/15th to 1 second, the mirror slap can create a long enough vibration, to render Camera Movement Blur in the image.

It’s not that mirror slap doesn’t cause vibration at other Shutter speeds. It is because in that range and around that range of Shutter Speeds, the mirror slap vibration can be a large portion of the period of time the shutter is open.

For faster Tv the shutter can be quick enough to alleviate the blur; and for slower Tv the period of vibration is a very small portion of the whole period of exposure.

About 1/15th to 1 second is the range of Shutter Speeds where I am wary in the field – so, IMO, for these clinical tests Mirror Up and Remote Release (or Delay Release) is always necessary, whatever the Shutter Speed is being used.

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There are too many variables and the OP is long gone.

Now I did miss that, Bill, needn't have wasted my time, eh?

No. Not for me at least - I read through all your tests. I took away knowledge from them. I have found this old thread quite interesting, (and also frustrating that Phil has not returned).

WW

[William W]

Beat me to it. The OP used a 15-85, which is a good lens. (I had one for several years.)

I have used the EF-S 15 to 85 also. At F/7.1 it is razor sharp.

Irrespective of my experience with that particular lens, my view is that the advice that one must use a Prime Lens to achieve ‘the sharpest pictures’ is simply flawed, as such sweeping statements simply cannot address all the variables, which are too numerous to begin enunciating, but include yet are not limited to the defining the comparatives of what? . . . Price? Aperture used? Dedicated Post Production Sharpening? . . . etc

Simple examples providing a range different outcomes, I expect:

1. EF 50 F/1.0L; or either of the EF 50 F/1.8 Mk I and MkII; or EF 50 F/1.4 or EF 50F/1.2L or EF 50 F/2.5 vs EF 24 to 70 F/2.8 MkII L set at FL = 50mm - all lenses at F/2.8, then all lenses used wide open.

2. EF 135 F/2L vs. all of the five EF 70 to 200L lenses set at FL =135mm, all lenses used at F/4, then all lenses used wide open

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I also disagree with the statement that a lens designed for FF will not produce sharp images if mounted on a crop sensor camera. A given crop may or may not less capable of rendering sharp images, but that is independent of the lens.

I concur.

WW

[William W]

The tread started without the most important information, what lens(es) were used. Later Donny puts some lenses in a response. . . . To get the sharpest pictures, you really should us a prime. . . . I bought a FF zoom lens with my DX camera some years ago. 24-85 and I barely got great real sharp pictures. But since I use it on a FF camera I love this lens because the pictures are really sharp now. My thought to use the FF lens on a DX camera was not my brightest idea. . .

Harrie,

Please see Posts 38; 39; and 42 in response to your advice, "To get the sharpest pictures, you really should us a prime"

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The differences is sharpness that were achieved between your lens on a DX camera (of some years old) and your newer model FX camera are not because of the lens being used on a different format camera: for example EVEN WHEN THE SHOOTING SCENARIOS ARE IDENTICAL and it is a perfect A/B comparison, my EF 135 F/2L USM Lens performs a lot better on a EOS 7DMkII than when it is used on (now collector’s) EOS D30 – and they are both APS-C Sensor Cameras.

Also, it’s important to consider that, a few years ago skill levels and familiarity would be different than now and, it’s quite common to transpose what we think is fact to being a fact for us which in image turn affects our performance - we see this in athletes all the time, but common example for me, are statement like: ”the (Canon) Kit Lens is garbage”; “you can’t use a tele-extender on a Zoom Lens the IQ suffers too much”; etc – people believe this stuff and because they believe it they reinforce it each time they pick up a Kit Lens by simply not using their skill and knowledge, to attempt to make a decent Photograph.

I think that you are severely limiting yourself and your Photography if you believe in these factoids as a Gospel.

WW

BTW, the OP did stipulate the lenses that were used: and that text is located Post 1.