[cprobertson1]

Sorry - just a quick sanity check!

Mirror lenses are supposed to be a little soft in the sharpness department, right?

Taking the first attached pic as an example (straight out of the camera): it's a little flat (to be expected for a catadioptric lens), but it's also a little soft, particularly around the edges.

Now, I can explain that by the shallow depth of field (according to online calculators, ~1cm at this distance (~4-5m)), obviously birds are thicker than that, and thus appear slightly blurry - but at the same time, the rest of the bird is till a little soft.

Q1: Is this sort of image quality to be expected under these conditions (moderate sunlight, distance of 4-5m with 600mm f/8 catadioptric lens)?

Q2: If I should be getting better image quality out of that lens, is it due to user error (for instance, maybe the focal plane just a pigeon smidgeon behind the bird, causing the softness), or is it a fault in the lens (Such as fogging/deterioration of a mirror)?

I have noticed that practically all my images are, to lesser or greater extent, at least a little on the soft side - but again, I've not been able to determine if it's me or whether the lens has a problem, or if it's just an intrinsic property of the lens itself!

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[Thagomizer]

Sorry - just a quick sanity check!

Mirror lenses are supposed to be a little soft in the sharpness department, right?

Taking the first attached pic as an example (straight out of the camera): it's a little flat (to be expected for a catadioptric lens), but it's also a little soft, particularly around the edges.

Now, I can explain that by the shallow depth of field (according to online calculators, ~1cm at this distance (~4-5m)), obviously birds are thicker than that, and thus appear slightly blurry - but at the same time, the rest of the bird is till a little soft.

Q1: Is this sort of image quality to be expected under these conditions (moderate sunlight, distance of 4-5m with 600mm f/8 catadioptric lens)?

Q2: If I should be getting better image quality out of that lens, is it due to user error (for instance, maybe the focal plane just a pigeon smidgeon behind the bird, causing the softness), or is it a fault in the lens (Such as fogging/deterioration of a mirror)?

I have noticed that practically all my images are, to lesser or greater extent, at least a little on the soft side - but again, I've not been able to determine if it's me or whether the lens has a problem, or if it's just an intrinsic property of the lens itself!

Every little bit of camera movement is going to have an impact on clarity when shooting with a long lens like this, so tripod, remote release or self timer will help reduce vibration in the system. I noticed your shutter speed was 1/80 second. That could be part of the problem there. Even on a tripod I like to shoot a lot faster than that with my mirrors. With handheld shooting I like to get faster than the 1/focal length shutter speed advised for handheld shutter speed. Higher ISO than 400 will let you shoot faster shutter speeds. Faster shutter speeds will help deal with subject motion as well as camera movement. Try some tests in good light (full sun if you can get it) with your camera on a tripod, using a remote or the self timer with a subject that isn't going to move. Don't shoot something too far away , or else you'll be dealing with heat shimmer, airborne haze and dust, etc. Shooting in these conditions using these techniques should give you the best case of what your set-up will give you. From there you can branch out and experiment with monopod or handheld shooting. These shots were all hand held, at ISO 800, 1/1000 sec., Tamron 500mm 55BB.