[Gander]

I bought a used Sigma 70-300DL Macro Super, but it looked like it had never been used. Clean, no buffs or scratches, lens clear etc. I use it on a Pentax K-5. But it seem almost every shot I take with it, they are oof. Very frustrating, concerning the reviews and rating for this lens.

I have been using the AF and the live view, the picture looks sharp everytime. Even live view on manual focus, looks sharp. Using the eyepiece or the screen same results. Now I will say that my eyes are not what they used to be, but even with my glasses I should end up with more that what I've been getting. When I up load the pictures to the computer and look at them, so many are just plain out of Focus. I swear that they were in focus at time of shot.

I have tried shooting at smaller Fstops and faster shutter speeds. It doesn't matter, pictures still are out of focus. It is hard to tell if it is focusing short or long. The K-5 has the ability to adjust the focus in camera. I've done that both ways up and down, didn't help. Somewhere on the forum, there is a program that you can boost the adjustments 90 plus both ways, I even tried that and that didn't seem to do much.

I've tried shoot on manual, even then it seems to come out oof. I can't believe that I just bought a lemon. There isn't any marks where someone may of dropped it. I just don't know. I have shot 100's of images through this lens.

My other lenses I don't have any problems with them. Not like this. I use a tripod almost all the time, its sturdy and heavy. Plus I hang something from the center under neath just to help. I'm almost always using the 2 second delay for each shot. I have a UV lens and a C-PL with a hood. I think I'm doing everything right.

So my question is, what do I do? I'm not ready for a float test.. yet.

[manacho2005]

Check your diopter adjustment on the viewfinder.

If you suspect you need focus adjustment, but are unsure of which way, I've found a quick way to tell.

Place your camera on a tripod or flat surface that can hold it still. Using live view, focus on something big and contrasty with the focal point in dead center.
-see where the focus ring sits
Then immediately switch out of live view and focus through the viewfinder(don't need to look through it). Making sure to focus with the center point, see which way the focus ring turned. You will need to adjust until the ring doesn't move any more.

Hope this helps. It helped me with my 170-500; thought it was a dud at first. If not well I hope you can get your money back.
Good Luck

[Gander]

Thanks Manacho I will give that a try, I will let you know how it turns out.

[Gander]

Manacho, I did what you suggested. I set up my K-5 on a tripod and had the Sigma 70-300 set at 70. Had it aimed at a contrasty image, a red and white sign board from a gas station. F-8, First I used live focus, then switched off the Live view and watched if the focus ring turned. It did, from behind the camera, it move a lot to the left. So I looked at the Fine adjustment setting and it was set at -10. I moved it to 0, and checked it again. it still moved but not as much. I moved the setting to +10 and checked it again. It moved slightly, vast difference then where it was. But still it moved. But I can't go any higher. I mentioned about a program that one of our members made or has that you can boost the fine focus settings past the -10/+10. I thought I had that program, but can't seem to find it.
If you know who that may be, I'd sure like to try it again with this lens.
Unfortunately taking the lens back to where I bought it is not an option. It's been longer than 10 months since I bought it. Would it be feasible to send it in to sigma and have then look at it or some other repair place? Do I need to send my K-5 with it?
Problem with buying something on fleebay or goodwill, is your taking a chance. My wife is sympathetic with me, bless her heart. She asked me the other day, "how many lenses do you need?" I said.. all of them! "oh okay".

Anybody have any other suggestions?

[manacho2005]

I haven't heard of an adjustment boost for the K5, but that doesn't mean it's not out there.
You could send it back for an adjustment; but seeing how you probably spent anywhere from $75-$100 on the lens, repair cost may justify getting a replacement.

[Sagitta]

In my experience with that lens (and mine is in bad, bad shape - I snapped something inside of it so I have to manually shove the lens back into itself to zoom out) it reeeally needs a honking amount of good light. It also will ALWAYS be fuzzy if you shoot close to 300mm - the lens is simply soft when shot long. Keeping the hood on is also good, it tends to be very blah without it.

That said, its very good at 70mm.

Honestly, if you have a dud its probably cheaper to just grab another used one, or if you don't mind spending $150 to $200 just get a brand new nicely warrantied DG version off of B&H or Amazon or somewhere.

Here are some shots I took at a parade on a bright sunny day at 70mm @ f/8. The parade wound up being interrupted by a freight train which allowed me to get a little creative.








The rest of that set was taken primarily (maybe completely) with that lens bouncing between 70mm and 150mm or so depending on what the subject was.

48th Annual Maine State Federation of Fire Fighter's Convention Parade - a set on Flickr