Tamron 70-200 vs Sigma 70-200

The body will have little or no effect on the focus speed of ring motor lenses. That is why when they used to test cameras for the title of fastest focusing they used non-ring motored 50mm F1.4 lenses.

The only way to speed up the ring motors would be to increase the voltage to the motor. that will of course shorten the life of the motor also. However the limiting factor is not the ring motor but the speed of the camera's processor in handling the data from the AF sensors. If the AF system (sensors + speed of the ring motor) is too fast for the processor then it will introduce overshoot and lengthen the time to focus.
Kent Gittings

Hello:

astigmate said:

Anyway, it's an absolutely false statement to say the tammy is bad @135mm, in fact my 1st lens was excellent at [email protected], but had some ghosting wide open except at 135mm ! (most gone @f3.5).

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Could you please explain how you know what my lens attributes are?...For that matter anyones elses but YOURS...IN reality the only thing you really know is what your lens does...So quit saying it's an absolutely false statement because frankly you are the one making the false statement...Mine is a tad softer at 130mm wide open and there have been many verifications of this as well...In fact I noticed this on mine long before I ever read any reviews...It sharpens right up by f/4 so for me it's a non issue...But to insinuate there are no lenses with this problem is false...

lw

astigmate said:

I've owned the tamron for a week prior to send it back for another
copy. The new lens is on it's way, I should have it soon. Anyway,
it's an absolutely false statement to say the tammy is bad @135mm, in
fact my 1st lens was excellent at [email protected], but had some ghosting
wide open except at 135mm ! (most gone @f3.5). I've also experienced
some random missfocus shots, like the DPR seem's to report, so for
theses reasons, I sent it back.

I hope the new one give me better results, if not, I will try the
sigma again and keep the better one.

awaldram said:

I've been trying to advise people of this but they just don't seem to
listen.

There seems to be some kind of Tamron hypnosis probably based on the
dpreview of the 2 lenses.

Whilst I agree the Tamron edges the Sigma at 200mm they are very even
at 70 and the Sigma blows the Tamron out the water at 135m.

And if you want to us the lens for sports/action then the decision is
a no brainer.

SDM is streets ahead when it comes to AF tracking.

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KentG said:

The body will have little or no effect on the focus speed of ring
motor lenses. That is why when they used to test cameras for the
title of fastest focusing they used non-ring motored 50mm F1.4 lenses.
The only way to speed up the ring motors would be to increase the
voltage to the motor. that will of course shorten the life of the
motor also. However the limiting factor is not the ring motor but the
speed of the camera's processor in handling the data from the AF
sensors. If the AF system (sensors + speed of the ring motor) is too
fast for the processor then it will introduce overshoot and lengthen
the time to focus.
Kent Gittings

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The other way to speed up the speed of sonic motor is use a faster motor ;-)

This is a function of the in lens controller and is part of the design. The down side is faster motor generally means lower torque which means slower AF.

Its not all about speed .

Also bear in mind the Sigma HSM is a lot faster on the canon body than the same lens on a Pentax body.

This is because its a close feedback loop . The lens moves ,checks with body, moves check with body etc.

As the Pentax body doesn't reply as quick it slows down the lens 'speed'

So we can expect to see improvements in existing sdm/hsm lenses as faster bodies appear.

One thing to remember about ring motors is that they have an encoder and encoder wheel combo. As the motor turns and the lens passes through focus the AF system saves the encoder position that it detected focus at so that it only needs to brake and return to the spot to be in focus. Any movement since will show up as refocusing time.

On micromotor lenses and motor in body setups they almost exclusively depend on the AF sensors to determine the focus spot. So you will often hear them go forward and then backwards fast then do a short jump forward and a micro movement back to be in focus. As you can see that is more steps than a ring motor would use.

What you may notice is that the ring motor system may not actually test the AF focus point as it is going back to the spot. It is this and the algorithm that powers it that may introduce errors. Especially in fast lenses with short DOF ranges.

So all the K10D cameras use a firmware update as opposed to actually doing a QC test at the factory like later bodies because there were no SDM lenses to test them with. I'm sure there are tweaks in the hardware that need to be done to calibrate a body for SDM/SW/USM/HSM use due to these factors. Updating the firmware does not take into account the little hardware variations that need to be tweaked to calibrate something of this complexity. I don't think Canon ever had to retro adapt an older model to use newer lens motors because they started out with some USM lenses right off the bat in the EOS system.

I praise Pentax for attempting to do this kind of update, since they obviously expected to do it.

However this is almost an example of a recall since not all the K10D would be calibrated in the blind to work correctly from scratch. So I am of the opinion that this should be a free service less a shipping charge. Similar to Sigma having to rechip their lenses and flashes for new camera bodies and flash modes.
Kent Gittings

Actually what you say is generally correct. If the camera's AF processing is not up to the speed of the len's motor system then the lens will travel longer in the primary direction before it gets the signal to return to encoder position xxx. This part can in fact be speeded up if a faster processor in a newer body is introduced. However if the lens system is only designed to match the speed of the current body a newer one with faster AF processing will not improve the AF speed any. Unless the maker has included flash firmware update capability in the lens that will allow faster algorithms to run.

If Sigma is using the same HSM system in Pentax lenses as they do in Canon I would expect an improvement in newer bodies. However I don't know if I would expect faster results in Pentax SDM lenses unless they over designed them from the start.
Time will tell.
Kent Gittings

KentG said:

The body will have little or no effect on the focus speed of ring
motor lenses.
title of fastest focusing they used non-ring motored 50mm F1.4 lenses.
The only way to speed up the ring motors would be to increase the
voltage to the motor. that will of course shorten the life of the
motor also. However the limiting factor is not the ring motor but the
speed of the camera's processor in handling the data from the AF
sensors. If the AF system (sensors + speed of the ring motor) is too
fast for the processor then it will introduce overshoot and lengthen
the time to focus.

Click to expand...

I agree although I would think the AF sensor itself in the K10d might be not so great in low light and is perhaps in need of an update as well for the sake of low light AF performance. But I'm just guessing--I really don't know all the reasons why the K10d is so slow in low light compared to, say, the Canon 40D.

Bart
--
http://zumbari.zenfolio.com

Hate to say this but the original Sigma 70-200/2.8 EX APO non-DG non-Macro is better than the current model with the exception of not having HSM in either Pentax or Minolta in the old days. Definitely sharper at 200mm at every aperture than the new MK II lens or the Pentax FA* 80-200/2.8 or the Minolta 80-200/2.8 HS-G APO. Slightly worse at 70mm than the Minolta. They both got the same 3.9 Photodo MTF rating at the time with one being better at the top and one at the bottom.

I tested these in the film days. Apparently some reviewers like me who did real testing have come to the same conclusion also in current tests. Theoretically the DG version, which has the same optics as the non-DG should be the same although I don't think they ever listed a Pentax version. They did make a non-DG Pentax version althought they tend to be rare.

By making the floating group travel farther for macro they have slightly compromised the performance at 200mm. This is the opinion of some lens reviewers.
Kent Gittings

Ev 6 is about that yes (5.93 to be exact... but who cares).

Depending on the position I can get I may use some panning (e.g. in gymnastics or indoor equestrian events) and than I can drop the shutter speed and reduce iso . Lowish EV6 is usually the limit indoors, but the EV 5 area comes up when I use spot metering.

With swimming EV 6 to EV 7 is quite common, and you still have the problem of the reflective surface causing some underexposure (though it varies from pool to pool). I found that with my k10d I could hardly get a properly sharp shot in waterpolo, unless I used the iso 1600. That was no succes as it was too noisy.

With the k20d there is more headroom with a workable iso 3200, but I might hop over to another brand with a fast AF and in body SR to get the most out of the lenses.

Btw, Trina found the Sigma faster than the 50-135 in (a poorly lit) store. I guess the difference is small, don't you ?

lock

--Finally a post to a thread that sticks to the subject matter and unbias opions are given.

Yours comments are the same comments i posted in another thread also adding the fact that the lenses reviewed are rarely tested on a Pentax camera.

I have a pentax 16-50*(much taked about qc issues)and the sigma 70 200 II. I.m lucky they are both keepers.None returned.

My moto from now on is.Choose a lens to meet your needs,Dont take reviews,and some comments made from forums to serioulsly,buy it from a store that will let you trial it and if not satisted guarentee a full refund.There is one store that i know in Sydney that will do it.
Fortunatley i,ve been lucky and have not had to return anything.

Yes I think the difference would be small as the AF speed imo is body related.

Whether the lenses are designed to match the body or can go faster with better processors in the body only time will tell.

I didn't notice any improvement when I tested the Sigma so any gains must be nominal.

Could be interesting to see a formal torture test of HSM Vs SDM in Pentax mount.

In the meantime I think there is no wrong answer Sigma V Tamron V DA* it depends in use.

So if you considering a Pro Tele Zoom just make sure your know what your needs are and the try and get a test drive.

Oh of interest on my new K20d my Old 70-200 EX F2.8 70mm end has sharpened up nicely (strange but true)

But it could be the AF is just more precise ? Or you think it's sharpness but actually what you are seeing is more detail/resolution ?

The latter was more or less my experience. I had the sigma 17-70 on the k10d that was soft at 17 mm (common knowledge). On the k20d I thought my aperture settings were false since at F/2.8 i got sharpness that approached F/4 on the k10d ! On the other hand, my old and trusted 50-200 did not gain a thing with the k20d...

Happy shooting !

lock

Could be just more resolution but in that case I'd expect the same quantitative improvement in my other lenses at 70mm , Which I'm not seeing.

I think its an AF thing , when I calibrated the Sigma the settings were so different (more than 60) from 70-200 I set for the 200 end on the k10d.

But on the K20d there is very little difference in af adjustment from 70-200 (less than 1).

So I think something been changed in the k20d AF system that is just not present in the k10D.

i have the 50-135 and i'm happy but want more reach.
i think i'll buy also a 70-200.

I have discovered this comparision of the three lenses for canon mount using a 1,4 teleconverter.
I hink the Tamron show a super performance compared to the other lenses.

In these days i have tried my nex 1,7 converter with the 50-135 and i have to say that the tamron sample kikcs my sample, consider anyway he use of a 1,7 converter against the 1,4.

Considering that the use of a 1,7 converter will produce good results with tamron also wide open in the center, and that pentax is coming out with a 1,4 sdm converter, i think this is a great plus for tamron.

sigma vs canon against tamron f4 280mm

sigma



canon



tamron



tamron still better!!!!

tamron at f8

Which tele-converter did you use for the Tamron? Does it provide AF? Also, is that the most recent version of the Sigma?

You have a note at the end saying Tamron at F/8--what's that mean? All the shots you posted are at F/4 with a 1.4x converter, right?

Bart
--
http://zumbari.zenfolio.com

i didnt take those shots.
those are shots you can find in this site made for canon equipment.
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=469

you can go there ad try different canon glasses.

i think the pentax 1,7 will keep autofocus with tamron and also he new pentax...

sigma converter seldom work with other brands, so i have read sofar.

Bart Hickman said:

Which tele-converter did you use for the Tamron? Does it provide AF?
Also, is that the most recent version of the Sigma?

You have a note at the end saying Tamron at F/8--what's that mean?
All the shots you posted are at F/4 with a 1.4x converter, right?

Bart
--
http://zumbari.zenfolio.com

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--
http://www.pbase.com/jon1976

jonny1976 said:

i think the pentax 1,7 will keep autofocus with tamron and also he
new pentax...

sigma converter seldom work with other brands, so i have read sofar.

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I think Pentax upcoming converter will only support in-lens focus motors (the roadmap says it's an SDM converter). So that would mean the Tamron is out of luck on the Pentax mount.

Bart
--
http://zumbari.zenfolio.com

.

I did a good amount of research (as much as I could, there wasn't really a huge amount of stuff out there,) and in the end, the Tamron just plain gave better images, from what I could find.

Here's f/2.8 @ 135mm - supposedly a weak FL/aperture:

I receive my Tamron copy about week ego; unfortunately it was a very bad one.
After AF adjustment in K20 focusing gets worse then w/o.

Thanks,

Michael

2 things.

First the Pentax 1.7x doesn't "keep" AF with any lens you put on it. It doesn't even use the lens AF under any circumstances. It stops the AF connection as it has no AF motor shaft pass through and does it's own AF inside the TC. SDM does not work through it either.

Second, I've seen examples of Tamron 1.4x TC with the SDM/power zoom contacts so those models will work fine with any Pentax SDM or Sigma HSM lens.

Kent Gittings