Tamron 28-75 sharper than Canon EF70-200 f/2.8L?

I know - shoot at actual subjects. I did that and wasn't happy with the Canon L sharpness at f/2.8. So, I shot this test pattern. The first is from the Canon L, 200mm f/2.8 and the second from the Tamron at 28mm, f/2.8. Both are 100% crops. I think the Tamron is much sharper. I took about 20 images with each lens, similar lighting, and the Tamron seems sharper at f/2.8 at 28mm, 50mm, and 75mm when compared to the Canon at 70, 135 and 200mm.

At 3x the cost I think this is a bit backwards.

Dan

None of the images look sharp to me. Did you use a tripod? Without a tripod, you aren't really comparing on a level field. It seems you are comparing apples and dump trucks here.....

They are two different lenses generally used for different purposes.

Also when testing, focal lengths should be the same.

ghms421 wrote in post #2605690
Also when testing, focal lengths should be the same.

That too......

exposures are different, and somehow you managed to get a higher exposure than the sun puts out but without flash

rstuntz wrote in post #2605685
None of the images look sharp to me. Did you use a tripod? Without a tripod, you aren't really comparing on a level field. It seems you are comparing apples and dump trucks here.....

They are two different lenses generally used for different purposes.

Isn't a tripod moot with shutter speeds of 1/4000 and faster?

I'm comparing two completely different lenses, both at their widest aperature and at their low and high end focal length. No, it isn't fair but the 70-200L has a reputation for being a very sharp lens. I don't know that the Tammy has that same rep.

I'm not comparing fairly. The L-glass should stomp the Tamron. I'm comparing at the low end of each lens' focal length and at the high end. Admittedly, not a fair comparison. However, should the L be sharp?

Both images (taken at different times, different light) are taken in full sun, 4000' elevation, crystal clear day. Perhaps the sun is brighter here than in Washington?

However, does exposure affect how sharp a lens is? I know underexposed images will be noisier when pushed but at least with this much light both lenses should be sharp. I think the Tamron is as sharp as it should be. It's the L that I think is soft.

This image was just taken with the 70-200L at approx. 12'. I took off the Canon UV/Haze sharp cut filter.

Put both of the lens at 70mm, and shoot the test pattern over again with the camera on a tripod. Then compare the images. It is pointless comparing images at different magnifications, whether final size or on the sensor.

I should also mention that the last image when viewed 100% in DPP with sharpness set to +5 (the camera default is +3) it is as sharp as the original image. I can't tell the difference between them.

I set sharpness to 0 for all of the images posted previously.

Dan

Wilt wrote in post #2605814
Put both of the lens at 70mm, and shoot the test pattern over again with the camera on a tripod. Then compare the images. It is pointless comparing images at different magnifications, whether final size or on the sensor.

At what shutter speed will a tripod have any impact?

I can't do a reasonable test since the Canon softness is primarily at 200mm and I don't have another lens to compare it to fairly. I can only compare max focal length to max focal length.

The point is that tripod removes all doubt...a variable that none of us know is how shaky or steady your hand is...there is motion even at 1/4000 sec., which is why bullets in a hand steadied rifle strike different points on a target. Even a sandbag is better than reliance on shutter speed alone.

Why can you not compare 70mm on the 70-200 vs. 70mm on the 28-75? I did once, at f/4 (since I do not own the 70-200 f/2.8...but the 70-200 f/4 lens is sharper anyway!) BTW, I could see no difference between the two!

'L' does not necessarily mean that the lens is 'better optically that all non-L's"!!! That is why I do not automatically bow to the 'L' god even though I own an L zoom.


If you insist on comparing max focal length, to be fair you MUST move your shooting point back by 2.8x to shoot the target with 200mm and compare to the 70mm on the 28-75mm; or back by 2.35x to compare 200mm to 85mm. That way any shakiness is better equalized by the fact that the same angular displacement is preserved for both lenses.

Thanks Wilt...let's see, a new Starbucks just opened here, I have a Rancillio coffee grinder and a Bunn drip maker...hmmm... but I can shoot a .5" group with my rifle at 100 yds!

I'll do that comparison tomorrow - the sun is setting now and I can't get enough light.

The differences could be my monitor (Gateway DCDi/Faroudia LCD) or my eyes or... The last image I posted with default sharpness (+3) in DPP was absolutely perfect.

Thanks for all the feedback.

dlpasco wrote in post #2606084
Thanks Wilt...let's see, a new Starbucks just opened here, I have a Rancillio coffee grinder and a Bunn drip maker...hmmm... but I can shoot a .5" group with my rifle at 100 yds!

OK, I'm not coming to date YOUR daughter! She is gonna have to come see me!

The point is to equalize the variables as much as possible. Even with your standard of shooting, both lenses AOV is different by shooting from the same point. In moving your shooting position, you present the same AOV to both lenses, when being used at the different focal lengths.

Additionally, you want the same amount of subject to be portrayed across the same number of pixels (approximately) so as to equalize the subject resolution, so that differences in sharpness are ONLY the lens.

) She's married so my marksmanship skills must not be that great! Actually, shooting a rifle for me means having a solid rest. You would think I would be able to transfer that knowledge.

I've got a lot of work to do with the 70-200 before I consider sending it back. I don't know if the lens is expected to be soft at f/2.8 or if I have a focusing problem or....?? Anyway, I'll shoot three hockey games tomorrow in good light. I'll open it up and see what happens.

Dan

its not expected to be soft at f/2.8 and if there was a tamron 28-75mm sharper than my own 70-200mm @ f/2.8 I wil eat my hat

By shooting at 200mm hand held you are not illustrating the lenses softness, but rather you are showing us camera shake and why you should use a tripod. nothing more.

CyberDyneSystems wrote in post #2606772
By shooting at 200mm hand held you are not illustrating the lenses softness, but rather you are showing us camera shake and why you should use a tripod. nothing more.

IS version!!