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Trying to fix the blur I see when shooting via a 75-300mm telephoto lens (this one) on a tripod, I enabled mirror lock-up in my Canon EOS 500D, and set a 2-second self-timer, so that after raising the mirror the camera made actual shot after a 2-second delay.

But whatever I try — releasing shutter from LiveView, doing shots without LiveView — I invariably get blurry photos. All this despite seeing a much sharper image in LiveView.

Below is an example of the shots I get with different focus points (which I adjusted using focus single-stepping commands by gPhoto). I shot at 300 mm focal length with aperture f/5.6 and exposure of 1/25 s. Test target was at 3.8 m away from the lens (this is the test environment at home, the problem reproduces with 50 m away objects outdoors). I get basically the same results with and without MLU.

different focus points with MLU

Here's the sharpest version I get in the LiveView:

LiveView sharpest image

Below is the comparison of a shot with exposure of 1/25 s and aperture f/8 (blurry frame) vs a shot with 1/60 s exposure with aperture f/5.6 (well-focused frame). Both were taken with MLU enabled.

Comparison of different exposures

What could be the reason for this inability to get a sharp image when shooting? Is there any other tool than MLU to help me make exposures of 1/25 s usable?

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    Doesn't look much like move blur to me. To eliminate the possibility of plain focus problems, take the picture with a much faster exposure (1/500 or more). If the trouble persists it is focus, if the trouble diminishes it is vibrations. – xenoid Oct 21 at 8:56
  • Or, if you really want to eliminate motion blur, use a flash instead. – Mattman944 Oct 21 at 13:49
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    @Mattman944 this might help for the 3.8 m test, but will fail with the 50 m range. – Ruslan Oct 21 at 14:38
  • @xenoid tried now with 1/60 s exposure, which gives a much sharper image. – Ruslan Oct 21 at 21:09
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    Are these JPGs from the camera or are you processing RAW outside the camera? – user10216038 Oct 21 at 22:24
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The mirror isn't the only source of vibration, the shutter causes vibration also. A more solid tripod will help, as well as weights hung on the tripod to minimize the vibration.

What tripod are you using? Post a picture of your setup.

I did some tests years ago, unfortunately, none with mirror lock-up.

http://www.suncoastcameraclub.org/Tips/Tripods.pdf

  • I'm not currently at home to tell exactly, but the tripod is something like Hama Star-61 (04161). – Ruslan Oct 21 at 14:40
  • OK, the model is indeed Hama Star 61 – Ruslan Oct 21 at 20:34
  • For serious work, you need a stronger tripod. Yours is what I would consider a travel tripod, Certainly better than nothing, and if you are carrying it a long way saving the weight may be worthwhile. – Mattman944 Oct 21 at 21:35
  • OK, seems your answer is spot-on. Now I've simply put the camera on a (quite solid) table, and the shot with 1/25 s now looks the same as I had with 1/60 s on the tripod. I wonder though, what is the use case for mirror lock-up then, if the shutter also results in such a large vibration? – Ruslan Oct 22 at 20:40
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  • Your first example shows the limits of optical viewfinder based PDAF using a dedicated AF sensor array independent of the main imaging sensor combined with the limits of the AF motor of your lens. The system is a so-called "open loop" one. The "ideal" focus position appears to have been somewhere between the third and fourth of the seven frame sequence.
  • This is also combined with a slow exposure time (1/25) that also leaves the images susceptible to camera vibration, which can have quite significant impact on images at longer focal lengths such as 300mm.
  • Keep in mind that with mirror lockup you may reduce or eliminate the influence of vibrations caused by the mirror movement, but you are not reducing the influence of vibrations due to shutter movement or camera movement caused by an unstable mount/tripod.
  • Also note that with viewfinder based PDAF and mirror lockup, AF is done before the mirror swings up. Any camera movement caused by mirror movement will be done after AF has been locked but before the image is captured. If the tripod is also unstable, then the camera position, even if all motion has subsided by the time of the exposure, may be different than the camera position when AF was performed.
  • Your second example shows the higher accuracy imaging sensor based CDAF is capable of when operating in a "closed loop" mode. There's also less time between AF and exposure, so less chance the camera is moving as far between AF and exposure.
  • Your third example shows higher amounts of motion blur when longer exposure times are used. Either the camera or your target was moving during the exposures. The smart money is on your camera/tripod not being rock-solid stable.
  • What role does AF play if I use focus single-stepping and don't trigger auto-focusing? – Ruslan Oct 22 at 5:43
  • It's still using the lens' AF motor to move the focus element, isn't it? In predetermined step sizes? – Michael C Oct 22 at 7:12
  • Yes, it's using the motor, but why would AF sensor have any influence on the outcome of such manual driving? – Ruslan Oct 22 at 8:16
  • Because when in OVF PDAF mode, the system is "open loop". That, coupled with the less precise focus position sensor in the EF 75-300mm f/4-5.6 III, means there's less ability for the system to correct itself if the actual amount of lens movement is different from the instructed amount of lens movement. – Michael C Oct 22 at 8:21
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Your last image sequence (comparing two shots at 1/25s ƒ/8 vs. 1/60s ƒ/5.6) does appear to show motion blur in the 1/25s image. Because you have already said you are using MLU, we can probably eliminate that as a vibration source (unless you can test with maybe a longer delay such as 5 seconds). If your tests have tripod fully extended, with an extended center column, try performing the tests with the center column retracted fully in the down position, and collapse the leg sections. Or better yet, set the camera on a pillow or folded blanket or towels on a table and retry the tests (still using MLU). That will completely eliminate vibration issues.

But I don't see much vibration in the first image sequence. I see general softness, lack of focus, and chromatic aberration. I think this is indicative of the lens, not vibration induced by the tripod.

The Canon EF 75-300mm f/4-5.6 III USM is known to be a mediocre lens, at best. From Bryan Carnathan's (the-digital-picture.com) review of the lens (emphasis is his):

[it is a] very cheap lens for this focal length range.

And the 75-300 III really is cheap. You usually get what you pay for - unfortunately this is the case with the 75-300 III.
...
Image quality from the Canon EF 75-300mm f/4-5.6 III USM Lens is also mediocre.

The 75-300 III is soft wide open at all focal lengths. Sharpness decreases as it zooms from 70mm to 300mm. However, the corners are softest at 70 and getting better by 300.

Corner and center softness decrease as the 75-300 III is stopped down.
...
The 75-300 III suffers from CA (Chromatic Aberration). Pincushioning is visible at 300mm.
...
If you care about great image quality and sharp photos, the Canon EF 75-300mm f/4-5.6 III USM Lens is not for you. And Photoshop cannot enhance details that are not there.

  • Even if vibration has subsided by the time of exposure, if ML is used and the tripod is not rock steady, there's a good chance the camera position may have changed slightly between when AF is performed prior to mirror movement and when exposure is done after mirror movement. – Michael C Oct 22 at 1:50
  • @MichaelC I get what you're saying, but the primary position change would be mostly in the vertical dimension (such as in the last image sequence), and secondarily in the lateral dimension, with very little motion in the optical axis dimension, which would be the primary contributor to AF inaccuracies. Also, at the apertures OP was using, the target is well within the depth of field for this to be the primary cause of the lack of sharpness, IMO. – scottbb Oct 22 at 1:56
  • Any movement cause by, for example, wind acting on the tripod can be in any direction. – Michael C Oct 22 at 2:00
  • f/5.6 is wide open at 300mm for that lens. We're also (I feel fairly safe in assuming) looking at cropped portions of test images at significantly higher magnifications than are typically assumed when DoF is typically calculated. One clue: The aspect ratio of the examples is not the native aspect ratio of that camera. – Michael C Oct 22 at 2:02
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    @MichaelC Agreed re: high magnification. OP said images were at 3.8m, which is fairly close for a 300mm. – scottbb Oct 22 at 2:06

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