Canon 5D Mk II with Tamron A20 AF28-300mm F/3.5-6.3 XR Di VC lens not very sharp

[qomsday]

Hi All,

Brand new to the boards and may as well be to the hobby. I was gifted the camera and lens in the title for Christmas a few months ago and am trying to work to understand how I can get better and what to do in different situations. The lens is a refurbished lens and generally the image quality is good (I think) but I'm running into some issues where the subjects of the image are not very sharp and I'd like to understand if it's a me issue or a lens issue.

Here's a couple of examples that when I was looking at them on my camera they looked great but when I got back to the PC it's a bit soft in the in focus areas:

ISO 640 109mm f/11 1/200 sec

ISO 640 109mm f/11 1/200 sec

ISO 160 168mm f/8 1/320 sec

ISO 160 168 mm f/8 1/320 sec

I would love some ideas from someone who is much more experienced than I am. I fully admit I'm not very good but am working to get better!

Some things I did see online that might contribute:

AF Micro Adjustments - I tried my hand at this a bit last night and have not yet had a chance to test outside yet, but the results didn't seem like that's the issue. I have no idea what forward or backward is when I'm doing the manual adjustment, I briefly looked at the manual but didn't see anything regarding how to tell which way is which. The 50mm prime I have (that I have not yet practiced/tested with the flowers, planning on doing that today) seemed to respond much better to the microadjustments and looked sharp.

Potentially a malfunctioning VC - I doubt this is it but have not tested it.

Maybe it's just the lens - I was talking with my dad and he suggested this. I've looked at some reviews when the lens came out and did see that it isn't as sharp as some, but I don't know what's normal and what's not.

Anyway I'm just trying to get better without jumping into the very tempting deep end of better glass. I'm going to do some further testing this weekend with some of my dad's equipment (Canon EF 24-70mm f2.8 II L USM and a Canon EF 70-200mm f2.8 II L USM) on my camera body with purposeful testing like this to see if there's anything going on with my camera body as well.

Again, any advice is welcome! I appreciate your time and hope you have a nice day!

[deebatman316]

AFMA adjusted doesn’t affect lens sharpness. It corrects for front or back focusing but not sharpness. Then stopping down very small such as F/22 introduces diffraction. Which leads to less sharp pictures. Are you sure VC is turned on it should be if shooting handheld. If using a tripod or any other stabilization device it should be turned off.

[qomsday]

My sharpness testing was done with a tripod, but the shots in my post (which were just for practice, not necessarily testing sharpness) were shot handheld. All of them with VC turned on, which can be changed obviously.

I would imagine f/22 would lead to some diffraction, but at f/8 and f/11 I would hope that this isn't the case. Really I just want to make sure I'm doing everything I can to make this lens work if possible!

[ebiggs1]

"I've looked at some reviews when the lens came out and did see that it isn't as sharp as some, but I don't know what's normal and what's not."

In this case I believe this is true.  The fact is, that lens doesn't have the best IQ you may very well be at its best. Anytime you try to make a lens with such a huge zoom ration like 10:1, you have to sacrifice something and that is usually IQ. Best zoom ranges should be 3:1 or close to it.

[ebiggs1]

"Are you sure VC is turned on ... If using a tripod or any other stabilization device it should be turned off."

 Some IS (VC) systems are more prone to these issues than others as there is a lot of variation in different lenses. Most of the time and in my own testing it doesn't make any difference.  But it's a good idea to test it yourself. It is very easy to see if turning off IS (VC) makes a noticeable difference in IQ wit your specific camera and lens.

IS (VC) is very much misunderstood and even by a lot of advance folks like the knowledgeable people on this forum.

IS (VC) actually has a limited SS range where it does any good or help at all. As your SS goes up 1/100-->1/1000+  IS (VC) becomes less and less help to nonresistant. On the other hand IS (VC) becomes less and less effective as SS become very slow.. The camera/lens ability to compensate for shake diminishes as longer exposure times increase. I suspect it is in this very slow SS range where some folks say to turn of IS (VC) because it can add vibrations trying to correct something that isn't there.