Sigma 70-200 F2.8


andy_bell

Link Posted 05/02/2014 - 11:05
After being just too late to acquire one of the two or three Sigma 100-300 zooms which have been sold on the forum in the last week or so, I have bitten the bullet and splashed out on a Sigma 70-200 F2.8 zoom, which on my K5II will give me an effective lens of 105-300 F2.8
I have also found out that my Tamron 1.4X Pz-AF MC4 Teleconverter works fine with this lens.
When comparing this chunk of glass against the wife's Pentax 55-300, two things are very noticeable, other than the physical size.....firstly the image is Much brighter....(no s**t Sherlock!) but most of all the difference in focus speed is amazing, the sigma is almost instant where the pentax is perhaps 3x slower...I guess this is mostly down to the max aperture available?

I just need some decent weather to have a good play with the lens to see what it can really do.
A few bits & Bobs
Last Edited by andy_bell on 05/02/2014 - 11:05

Chrism8

Link Posted 05/02/2014 - 11:21
I'm fortunate to have both Sigma's and they are outstanding, plus focus speed is really good on a K5ii
Chris

www.chrismillsphotography.co.uk

" A Hangover is something that occupies the Head you neglected to use the night before".

-------------------------------------------------------------
K1 - Sigma 85mm F1.4, Pentax DFA 150 -450 F4.5 / 5.6, Pentax DFA* 24 - 70 F2.8

Samyang 14mm F2.8, Pentax DFA* 70-200 F2.8

K3iii + K3ii + K5iis converted to IR, Sigma 17 - 70 F2.8, Pentax 55 - 300 F4.5 / F5.6 PLM

Mike-P

Link Posted 05/02/2014 - 12:13
I would recommend using minus EV compensation of at least half a stop when using a 1.4x converter (and more when using a 2x). This is because 99.9% of teleconverters are non reporting on Pentax and so the camera is still metering as if it wasn't there.
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andy_bell

Link Posted 05/02/2014 - 13:03
Hey Mike, thanks for that snippet, I didn't know that, I have noticed that the lens reports its "full frame" focal length, even though on the Pentax body it is X1.5 times that, it would have been nice of them to correct the reporting so it is recorded correctly by the camera.
A few bits & Bobs

percy

Link Posted 05/02/2014 - 13:28
andy_bell wrote:
. . . . . Sigma 70-200 F2.8 zoom . . . . Tamron 1.4X Pz-AF MC4 Teleconverter

I have this setup too, and like you I find the AF speed is much better. It works pretty well (although obviously not as fast) with the teleconverter on as well.

Mike-P wrote:
I would recommend using minus EV compensation of at least half a stop when using a 1.4x converter (and more when using a 2x). This is because 99.9% of teleconverters are non reporting on Pentax and so the camera is still metering as if it wasn't there.

Yes, a very useful tip. Thank you.

gwing

Link Posted 05/02/2014 - 15:15
andy_bell wrote:
Hey Mike, thanks for that snippet, I didn't know that, I have noticed that the lens reports its "full frame" focal length, even though on the Pentax body it is X1.5 times that, it would have been nice of them to correct the reporting so it is recorded correctly by the camera.

Nope. A 200mm lens is a 200mm lens whether it is mounted on a FF or APSC sensor. A 200mm lens on a Pentax APSC body is NOT a 300mm lens.

It would however be nice if a 200mm lens plus 1.4x converter reported as 280mm.

ilovesaabs

Link Posted 05/02/2014 - 16:22
Actually the raw software will tell you what the actual focal length used was..and it's equivalent in 35mm

Sigmas, I have found, tend not to report very well, even if connected directly with the body...regardless of make of camera body..
AKA Welshwizard/PWynneJ
Assorted Pentax/Nikon/Mamiya stuff

Stuey

Link Posted 05/02/2014 - 19:58
The us forum has a comparison with the 55-300 and the 60-250 - the af comparison is interesting as is this

I have been tempted by the 70-200 sigma but just won't use it enough to make it viable

Glad to hear that the af is quick with it though
K10D, K5 plus plenty of clueless enthusiasm.

My Flickr site link

Daniel Bridge

Link Posted 05/02/2014 - 23:07
Mike-P wrote:
I would recommend using minus EV compensation of at least half a stop when using a 1.4x converter (and more when using a 2x). This is because 99.9% of teleconverters are non reporting on Pentax and so the camera is still metering as if it wasn't there.

But why does the camera need to know it's there? It's just measuring the physical amount of light reaching it's lightmeter, which is going to be less when the convertor's in use. You don't have to apply -10EV of compensation if you're using a Big Stopper...

Dan
K-3, a macro lens and a DA*300mm...

Mike-P

Link Posted 05/02/2014 - 23:41
No idea, I have never looked into it.

all I know is that every Pentax camera I have had overexposes when using any teleconverter other than the 1.7X adapter (which is reporting on Pentax lenses). It is most noticeable when using Sigma's 100-300mm f4 and the matching 2x converter ... however it doesn't happen with my 7D and the same lens/converter combo (which is fully reporting).
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Daniel Bridge

Link Posted 05/02/2014 - 23:57
How odd. I'll have to try it sometime with my Tamron, never noticed it happening, but then again haven't used the thing for some time.

Dan
K-3, a macro lens and a DA*300mm...

Mike-P

Link Posted 06/02/2014 - 08:54
How very strange.

I thought I would take a couple of shots with the Sigma 100-300mm f4 and 2x converter to post up and it's actually pretty much spot on. I haven't had cause to use this combination with the K-5II since I got it 12 months ago but I am 100% certain I used to have problems with the K10D/K-20D/K-7/K-5 MKI.

I remember reading when the K-5II was first released that it was a lot better metering with manual lenses so maybe it's a knock on effect.

Or maybe I'm just going senile.

Edit: just looked at both test subjects and in each one (using TAv mode) the auto ISO jumped from 1600 to 6400.
. My Flickr
Last Edited by Mike-P on 06/02/2014 - 09:11

Steep

Link Posted 06/02/2014 - 11:42
andy_bell wrote:
Sigma 70-200 F2.8 zoom, which on my K5II will give me an effective lens of 105-300 F2.8

No, it won't. The equivalent to 35mm measurement is hype dreamed up by marketers to make you think you're getting more than you are. The focal length of the lens does not change.

johnriley

Link Posted 06/02/2014 - 12:34
We all understand what it means though. The "35mm equivalent" was important so that people understood what the field of view was compared to the film cameras they were used to.

There were, and are, many different formats in digital, so a standard way of comparing is actually quite useful.

We know the focal length doesn't change, but the field of view does.
Best regards, John
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