[RightOnTime]

Howdo folks. First proper post and it's a bit of a cry for help...

Splashed out 550 notes on a Tamron 70-200mm and trying to decide whether I have a bad copy or just unrealistic expectations. I'm not a pixel peeper and I don;'t care too much about sharpness as long as I get a solid picture, but wide open at 200mm it feels pretty much unusable due to a weird 'glowing' softness. Not 'soft' as in 'unsharp', but more of a wide bright glow/halo around details, like you get with a crappy teleconverter. It seems to get better as you back off towards wider angles, a little soft still at 70mm but more in the acceptable range. Whereas at 200mm it's noticeable even on a smallish thumbnail, an obvious haze that looks like a dodgy soft-focus filter. It also looks a little overexposed at 2.8.

I'm 90% certain it's nothing to do with front/back focus. Stopping down to f3.2 (or 3.5, see below) pretty much kills the softness straight away and from f4 it's sharper than Wolverine's nail clippers.

On a separate note, I can't select f/3.2 at 200mm. if I set it at a wider angle and then zoom to 200mm, it jumps to either 2.8 or 3.5. Is this a normal quirk of this lens?



Here's some examples, all taken at 200mm. Forgive the bland shots, just used my backyard as a test bench.

90% crop: f2.8


90% crop: f4


f3.5


f2.8

Basically, if you own or have used this lens...is this glow normal at 200mm wide open? I'm not a pixel peeper and I'm not expecting X-TREME SHARPNESS™, but this glowy thing is unpleasant and it's left me feeling a bit disappointed. I've got a week to make up my mind whether to return the lens, so i need a reality check to see if I'm just being fussy or I have a lemon here!


(PS: I'm not buying the whole 'oh yeah it's soft at 2.8, but it's great at f4!' thing. You can get a Canon 70-200L f4 for £50 less than this Tamron, and frankly that's a better lens in every possible way except maximum aperture. Obviously that's no consolation to us Pentax folks, but it shows that the Tamron is not worth the money if you're only able to use it stopped down...)

[shardulm]

Wonder if there was any condensation on the lens/sensor that contributed to this. These are more hazy kinds than soft. But I may be wrong.

[RightOnTime]

Wonder if there was any condensation on the lens/sensor that contributed to this. These are more hazy kinds than soft. But I may be wrong.

Glad you agree, it doesn't look like typical softness! I see what you mean but condensation seems unlikely, it was pretty cold outdoors and I did a couple of comparison shots with a DA 50 1.8 which were absolutely fine. The plot thickens...

[northcoastgreg]

My copy of the Tamron 70-200 is sharp wide open and tack sharp by f4. I can't tell from the examples provided above whether the version in question has issues. The images are shot very close-up, so the DOF is extremely narrow. Shots further away with more DOF might be more illustrative.

Here's an f2.8 200mm shot from my copy taken from a decent distance. Click on it to zoom in:

[Pixelhdr]

The copy I had many years ago had a similar behavior except it was the short end that was bad while the long end was OK. I sent it to Tamron for warranty repair. Despite the fact that they said was cleaned and recalibrated, there was no difference when it was returned to me. I since sold the lens and picked up a Sigma 70-200 OS which I still have. On a similar subject, I have a Tamron 17-50 since 2007 but it started to have uncorrectable focus problem about a year ago. I paid Tamron to fix it but they could not; the repair cost was totally wasted. I now don't have much confidence in Tamron.

[leekil]

Not sure about the lens, but the cat looks like a lemon!

[Johndav]

I have this lens and it is sharp wide open so something is amiss

[JinDesu]

Hopefully this can help, as I made a bunch of shots at various apertures and focal distances with the Tamron to compare to the Sigma.

Tamron 70-200 F2.8 & Sigma 70-200 F2.8 EX DG HSM II | Flickr

[clackers]

Doesn't look good.

Like all new purchases costing hundreds of dollars, do your AF micro adjustments, then test for decentreing, and send back to the seller if it's not up to scratch.

[Scorpio71GR]

Something just does not seem right this lens. I could not find any 200mm f2.8 examples. I usually avoid shooting wide open at 200mm because of my own limitations not my lens. As for 200mm and f3.2 this should not be an issue.

This was taken at 200mm f3.2 ISO 5000 on my K3 with the Tamron 70-200.

[JeffB]

It really is not practical for us to judge "softness" of a particular lens based on the photos you posted. There are too many variables not accounted for: exposure, tripod, AF/MF, AF point, SR?

Basic guidelines for testing:
https://www.lensrentals.com/blog/2010/11/how-to-test-a-lens/
How to Test Your Lens | B&H Explora

Source for downloadable* test chart:
ISO 12233 Test Chart

*Note that by downloading and printing your own chart versus buying one you are adding the variables of your printer into the mix.

If you really want to make sure you are testing your lens and not your handholding technique or your tripod stability, try putting the camera+lens on a sandbag or similar to completely eliminate movement. Be sure in-camera SR is OFF.

[manufocus]

My lens exhibits the same glow at f2.8 which is gone as well at f3.5/4. However I haven't seen any lens that won't show this behavior wide open. Even the Praised M 50mm/f1.7 shows the same. (As did the K135/2.5 or K200/4). If you look at the in-depth review of the DA* 200 at the Center sharpness sample image at f2.8 you will see the same glow (https://www.pentaxforums.com/reviews/smc-da-200mm-f28-sdm/sharpness.html).
The effect is increased if focus is even slightly off, so you might want to check with manual focusing if the lens needs a little bit of adjustment (mine wants ~-3)

If you zoom in on the tiger you see something similar in the fur, even though not as pronounced. Some expert for lighting can surely help :-)

I'm not quite sure exatly how this happens but I think it is related to the fact that you use more of the edges of each single lens.

Someone also once stated that in older lenses this softness was wanted to achieve certain effects, especially in portraiture where pixelpeeping won't do the human race any good at all.

[bdery]

It looks about right for 200mm wide open for this lens. You can look at the review of the Pentax 70-200mm where I compare it to the Tamron 70-200mm. Wide open is never the Tamron's strong suit.

[GeneV]

The vast majority of my shots are at F/4-5.6, and they are razor sharp. It is probably because I use either manual set at something other than 2.8, or the MTF program line, but I have very few photos on this lens at f/2.8. The ones I have are in such challenging light conditions that it would be hard to separate the effects of the lens from the effects of High ISO. Wide open is not really my normal use of the lens.

[Philtandir]

My Tamron 70-200 has the exact same problem. To the extent that it is unusable at f2.8 unless I want a special effect. Since I bought it second hand for an insanely good price, I decided to live with it as the lens is usable at f3.2 (much less softness), sharp from f3.5 (no softness) and VERY sharp at f4 and more. Still, it was a bummer when I got it, especially since there are samples out there that does not seem to exhibit the problem as much (it is there, but not "unusably" bad). The tiger picture in this thread would be such an example. I could never do such a picture at f2.8 with my copy of the Tamron, and it is not a question of back of front focus: I have extensively tested the lens to optimize its performance. I would get the same softness as what is shown on your examples. My fault for not testing it more when I bought it, I guess. At least, stopped down a bit, it is a fantastic lens with which I have taken some great pictures.