[slr_neophyte]

If your lens is calibrated properly for front and back focus I'd send it unfit repair. There is a thin piece of plastic lens in between the glass ones that can warp and cause focus issues. If your in Europe send it in to Alan Marlow in the UK for repair. It shouldn't cost too much

How do you calibrate a lens? Are you talking about the AF fine tuning function? Also, if it is a front and back focus issue - wouldn't I be having issues at ALL focal lengths (the whole range from 55-300)? I have several shots taken from a couple weeks ago between the 55-230 range that are in focus and quite sharp.

[stevebrot]

Also, if it is a front and back focus issue - wouldn't I be having issues at ALL focal lengths (the whole range from 55-300)?

Not necessarily. The optical path changes as the lens zooms. As a result the dynamics of autofocus change as well*. That is one of the weak points of the AF fine adjust feature. Conventional wisdom is to do the fine adjust at moderate distance and the most commonly used focal length. Be aware that any changes have the potential to screw things up at other distance/focal length combinations.


Steve

* For recent model Sigma zooms that support the lens calibration Dock, calibration is done at multiple distances at each of several focal lengths.

[Scorpio71GR]

I have the HD 55-300 and I find it to be pretty sharp. These both taken from across a river about 30-40 meters away. Taken at 300mm @ f8.0. I never shoot wide-open at 300mm with this lens.







Michael

[slr_neophyte]

I have the HD 55-300 and I find it to be pretty sharp. These both taken from across a river about 30-40 meters away. Taken at 300mm @ f8.0. I never shoot wide-open at 300mm with this lens.







Michael

Nice shots - I would guess the HD 55-300 is far superior to mine (the DA 55-300)

[paulh]

Nice shots - I would guess the HD 55-300 is far superior to mine (the DA 55-300)

Most reviews I've read show the HD55-300 to be only slightly better optically than the DA version, due to newer coatings.

[Rondec]

Nice shots - I would guess the HD 55-300 is far superior to mine (the DA 55-300)

I think they are about the same.

I do usually stop the 55-300 down to f8 when I am shooting, but it does seem pretty sharp to me as long as you hit your focus.

[Scorpio71GR]

The only real difference is the coating, optically I believe they are identical. I never owned the smc version, but I do not think the HD version is in any way superior. It took me awhile to learn this lens. As stated by Rondec, you really have to nail the focus. This is were quick shift comes in handy for me.

Michael

[C_Jones]

I ran into some frustrating issues today with focusing and sharpness. Unfortunately I deleted the photos so am not attaching any samples for reference. I was using my K-5 II, with the DA 55-300. I was about 30-40 meters away from my subject (a seagull on a post in the ocean). My lens was at maximum zoom (300mm), shutter speed was 1/4000 (I think), and aperture was 5.6. I used a tripod for maximum stability, set the self timer so I would not have to touch the camera, and regardless of how many shots I tried the subject was still slightly out of focus (not tack sharp). I'm just wondering if this is a problem with the lens? Something I am doing wrong? Or, could it be the slight wind that existed? I was doing my best to shelter my camera from the wind during the shots. I'm using a pretty good tripod (Sirui T-025X).

Any thoughts / advice is appreciated. Thanks!

Just a suggestion. TAV mode, F10 - F13, 320 Shutter speed, Continuous AF mode, Center AF Point mode, Spot Metering mode, light (minor) adjustment with EV if needed, and handheld. If shooting something like a bird in flight (ex. Seagull), TAV mode, 1000 Shutter speed, F8, no EV if good light, to avoid possible underside shadow +3 EV if desired, and handheld.