[nupentaxian]

damnit i was thinking of getting the da*50-135mm, but this is so tempting....

[raz-0]

For pentax users, AF accuracy depends on the dslr body since it is the body's motor that is used for AF operations.

Therefore AF reviews on other mounts should not be taken into consideration, imho.

Anyway, I should receive it tomorrow or (in the worse case scenario) the day after tomorrow.
I will keep you posted

I'm counting on the same thing rregarding the focus. Also that even if it has some slop, the pentax double checking that folks complain about constantly might pay off in mitigating the problem.

Mine's out on the truck for delivery as I type.

[ftpaddict]

Mine's out on the truck for delivery as I type.

I haaaaaate you

[happyant]

so your saying the Tamron has the superior image quality, over the sigma?

ahh soo tempting to buy this..

[Shashinki]

Tamron no better than Sigma! boo! hiss! nah, just kidding..

[happyant]

Tamron no better than Sigma! boo! hiss! nah, just kidding..

That does not give me too much confidence :P

[Shashinki]

Let's just say (if I can try to be serious for once) that for some, the AF-speed and less CA of the Sigma will be the better choice.

Tamron has the general IQ going for them according to DPreview.

[nupentaxian]

ok who bought all of these at b&h? lol

[raz-0]

so your saying the Tamron has the superior image quality, over the sigma?

ahh soo tempting to buy this..

No, the tamron has slightly lower resolution and a slightly less sharp image than the sigma. At least in the center wide open. bump it one stop, and the tamron is much more uniform corner to corner across most of it's range. The new sigma 70-200 (macro version as opposed to old non macro), has all sorts of softness in the edges.

Given that a lot of my preferred composition is not dead center, this seems preferable to me, although the sigma is probably better at 2.8 through a greater range and has more forgiving focus travel which will probably result in less overshoot under low light. However at 2.8 and 200, my most likely scenario for needing the speed, the tamron is sharper through most of the frame according to dpreviews charts. The sigma, from the tests and sample images seems to be weighted towards best quality at the 70mm end of things. Put the dpreview flash toy into fullscreen cmparison mode, and play around. It's got a lot of info in one small space once you figure out how to read it.

I'd avoid both for a full frame sensor, and given the prices, they are both a compromise.

Let's just say (if I can try to be serious for once) that for some, the AF-speed and less CA of the Sigma will be the better choice.

Tamron has the general IQ going for them according to DPreview.

All the sample images I have seen and all the test seems to indicate tha CA on the sigma is worse, especially in OOF areas and in the corners if you get a sample with worse than average corner softness. The dpreview review seems to agree the tamron has less CA, and none of the OOF CA issues. The new sigma is not as good as the old non-macro version for CA, which was frankly damn good compared to most any lens.

ok who bought all of these at b&h? lol

Me, I have mine right here. But nothing good to take a picture of that shows off the lens since by the time I got to unbox it and play it was well after dark.

So far all I can say is that the dpreview take on the AF/MF focusing switch and the touchiness of manual focusing is understated if anything. switching from AF to MF can move the focus ring as much as 1/16th of an inch, and given the short focus throw, that's a LOT.

I don't really have enough light to even begin to talk about purple fringing or CA.

The macro mode is reasonably effective for what it is.

nothing I have experienced with it as yet would contradict the dpreview take on the lens.

As far as focusing, it's a bit more picky about low light focusing than my sigma 17-70 is, but not too much. I'd chalk it up to the field of view and short focus travel exacerbating worst case scenarios. It's pretty usable though. But then again, I'm of the school of theough that pentax's low light AF isn't too bad if you play around and practice with some torture tests and figure out what helps and hurts the AF system. Like pretty much every other pentax lens, you can stop it perma-hunting at one end of the focus range by pointing it at a light fixture with the edge of the fixture near the AF zone.


it's not much, but below is a handheld shot of my work bench that needs cleaning up desperately.

85.7mm, iso 800, f2.8, 1/10 second handheld (braced against doorjam) SR on. It is illuminated with a single 23watt bare compact flourescent bulb (tungsten tinted) from the overhead fixture. Straight out of the camera with a custom WB to raw, and adobe ACR on my defaults for the k10d (aka, my usual workflow with no PP). Center cross sensor for AF located over top "A/O paper" line of text. Green button camera set for multi-segment metering.



here's the full size jpeg.

http://www.bloodimage.com/tamron/IMGP4526.jpg

Here is a composite 100%. Same basic setup. Left to right, single image, two sequential shots, three sequential shots. Crop attempts to correct for my human wobble as it was handheld. 3 chances to AF, and some sequential images to see how SR compensates for my shortcomings. Not as controlled as the DPreview focus test, but the pentax AF system seems to deal reasonably well with this lens, and from what I seei n the viewfinder, it is the double check that so many people bitch about that keeps it from being a trainwreck. The AF seems to not have an issue as far as I can tell. Although given the lighting, I'm at the limit of SR's ability to compensate for any of my tremors and mirror slap.



Hope that gives you find the feedback useful.

ttp://www.bloodimage.com/tamron/tamron_seq_focus.jpg

[kojuo]

Took a few shots with the lens

First, bear in mind that my body experiences tiny BF with my 35fa2, and I found it to be the case with the tamron as well, but nothing to do with the lens, don't freak out


so...

AF Accuracy
Lens focuses with accuracy any subject with "normal" contrast.

What bugs me a bit is when it comes to focusing on subject with too little contrast.
It's like the lens goes blind and focuses all the way down to the minimal focus distance, even when it needed to go toward the infinity range. Which is where the macro focusing feature doesn't help, since it adds more range to the focusing :ugh:
This is the only thing I can find about AF against this lens.

But from the lens or the body, which is really responsible ?

I have too few experience with AF lens to tell, if someone has the answer, I would like to know.


AF Speed
No issue here imho.
I find it quite fast, which is good cause it balances a bit with the searching AF problem said earlier.
"Nervous" would be a good word to describe it, perhaps


AF Noise
Moderate I would say. It's not silence, but it's not HSM either so no need to cry about it imho
Don't expect something as bad as what you get with the kit lens though, it's quite smoother !

Actually, the noise is very much like the one when focusing with the 35fa2

I wouldn't say it's a bad "surprise"



This whole post was about AF. Now to talk about Sharpness .. well ... no need to say more, looks like what dpreview put in its review .. great @ 200/2.8 (at least compared with the old 80-200/2.8 adaptall I used until a few weeks ago)


So, I personally have no regrets in buying this lens.
Now, I just need to correct the BF issue on my body to fully appreciate it wide-open !


Regards !


P.S: super-yummy bokeh !

[kenyee]

What bugs me a bit is when it comes to focusing on subject with too little contrast.
It's like the lens goes blind and focuses all the way down to the minimal focus distance, even when it needed to go toward the infinity range. Which is where the macro focusing feature doesn't help, since it adds more range to the focusing :ugh:
But from the lens or the body, which is really responsible ?

All lenses do that on pretty much all bodies (including non-Pentax) unless the lens has a focus limiter feature.
Take your FA35 and point it at a grey wall to see what I mean :-)

Could you run a few BF/FF tests? Do it wide open at 70, 135, 200 and shoot some subjects at a diagonal like I did w/ my Tamron 28-75 testing thread...

[kojuo]

All lenses do that on pretty much all bodies (including non-Pentax) unless the lens has a focus limiter feature.
Take your FA35 and point it at a grey wall to see what I mean :-)

Ok, wasn't too sure about it

Could you run a few BF/FF tests? Do it wide open at 70, 135, 200 and shoot some subjects at a diagonal like I did w/ my Tamron 28-75 testing thread...

The only thing is, I already have "native" BF from the body (which I discovered with my FA35) so it behaves the same with the tamron.
It's slight, but still quite noticeable @ 200/2.8 when focusing at greater distances than ~10meters

do you still want me to run the tests ?

I will try in a few days to correct the BF using the debug mode. First I have to find a usb cable , lost mine :-/

[kenyee]

I will try in a few days to correct the BF using the debug mode. First I have to find a usb cable , lost mine :-/

If you're going to correct BF, do that first.
I don't see BF on mine even when using my 50/1.4...

ken

[blwnhr]

The new sigma 70-200 (macro version as opposed to old non macro), has all sorts of softness in the edges.

Shot with the new (Series 2) Sigma Macro (not Pentax mount, obviously). Focus is on the alloy between the 2 blue plates.

Full res shot is sharp as a tack. Reduced size image doesn't do it justice.

1/250, f/4, ISO-200, 82mm.

[gavinhw]

For a comparison of the Sigma and Tamron 70-200mm's, check out this page.