[linaix]

Hello,

I have a Canon 5D mark II and want to buy a new lens. Basically I was going to buy the SIGMA 24-70 DG macro, but then I have seen that there was the HSM version (but with bokeh issues) and the new Sigma 17-70 HSM. Now I am quite lost. In the analysis, it seems that the 17-70 has better specs. But it does not open at 2.8 in the full range. So I am just wondering if any of you has tested those lenses and if you can tell me which one you prefer ? I use a lot the bokeh in my pictures. Maybe if there are other and better lenses for less than 1000 $ ?



Thanks

[wim]

The 17-70 is an APS-C lens, and the 24-70 a FF lens. I guess that makes the choice easier. In FF terms the 17-70 for APS-C would be similar to a 27-112 F/5-F/6.3 (or thereabouts) zoom for FF, so the closest would either be the EF 28-135 IS or the 24-105L. If you need the extra f-stops, the 24-70 is a good choice.Kind regards, Wim

[linaix]

Thank you for your answer, I really thought it was a FF lens... Then I have an other question, for the moment my camera has difficulties for autofocus when it becomes a little bit dark. I don't know if it is normal or if it is because I am not using an HSM lens. Any idea ?

[wim]

What lens are you using and how dark is it?



Any lens with a maximum aperture smaller than F/2.8, i.e., a larger number than F/2.8, will have more of a problem with AF than a lens with a maximum aperture of F/2.8 or faster.



I do a lot of low light photography with the 5D II, and i generally do not have any problems,, as I use all fast primes, except with the 100-400, which does have problems in the dark.



BTW, I rarely use anything but the centre AF point, which is more sensitive than the others.



Before I forget, especially when th elight gets low, you need to try and focus on somethign with a good contrast transition. Focusing on something of a single colour, same contrast, doesn't really work, and unlike the human eye, an AF sensor can't really take its surroundings into account, unles syou use many AF points, but that is counterproductive in very low light circumstances anyway.



Kind regards, Wim

[willhl]

Have you considered the Tamron 28-75? I've not used it but I've heard good things.

[netrex]

[quote name='Will HL' date='04 June 2010 - 12:43 AM' timestamp='1275608593' post='168']

Have you considered the Tamron 28-75? I've not used it but I've heard good things.

[/quote]

I've had that lens, I used it for my Pentax K10D for a while, and it was good. Sharp at all apertures, but lost some contrast at f/2.8, but still sharp though.

[linaix]

Actually I'm mostly using the canon 50mm at 1.8. For the focusing, in the dark I mean at sunset or in the night with lights. I was used to do night shooting with an old EOS, at that time I had less problems for focusing. A friend told me that the focusing depends of the quality of motorisation, so that's why I think I should go for HSM, but still I don't know if it really makes a change. If it makes a change then I should not take the Sigma 24-70 ?

[linaix]

[quote name='Alexander (former netrex)' date='04 June 2010 - 06:19 AM' timestamp='1275628783' post='172']

I've had that lens, I used it for my Pentax K10D for a while, and it was good. Sharp at all apertures, but lost some contrast at f/2.8, but still sharp though.

[/quote]



In the photozone test, they say "The Tamron AF 28-75mm f/2.8 SP XR may shine with glory on APS-C DSLRs but it has found its master within the full format scope". The problem is to know who is the master :-p Maybe I should better go for an other zoom range ?

[Brightcolours]

To avoid confusion in future:



APS-C lenses from the different manufacturers have the following codes in their "names":



Canon: EF-S (full frame 135 format: EF)

Sigma: DC (full frame: DG)

Tamron: Di II (full frame: Di)

Tokina: DX (full frame: nothing)



Do not stare yourself blind on photozone test data or conclusions by the reviewer, they are merely a help in comparing lenses. And as always, also use other sources to get a more complete view of the character of lenses.

Also, you say you did not have similar problems on your old EOS, I am guessing you mean one of the film cameras. With film you never really looked at pixel level, so digital always will be disadvantaged here, in a sense. It is true that the 50mm f1.8 is not a stellar-ly accurate focusser, and focussing problems should first be blamed on that lens, rather than on the camera body. You can (obviously) try how another fast prime, with a Canon USM motor, will focus in the same light conditions, or even the Canon EF 35mm f2 (which does not have an USM motor, but is quite accurate in AF, also in lower light conditions).



Both the Sigma 24-70 f2.8 HSM version and the Tokina 28-75mm f2.8 are good lenses for their money. I personally would prefer the Sigma over the Tamron because of the Tamron's AF motor and the build quality difference. But the Tamron is hugely less expensive.



Another interesting lens (very affordable but not very fast) in this segment is the Canon EF 28-105mm f3.5-5.6 USM (II). It is not super sharp, yet it is a lovely lens. Fast and accurate AF, nice colours and contrast, a little affordable hidden gem in the Canon line up.

[toni-a]

Sigma 17-70 isn't made for 5D, forget about it.

Had the Sigma 24-70f2.8 DG macro, I used it on 30D.

An excellent lens,had two samples, on first one had focus problems, it was replaced the new lens AF was fast and precise but very noisy, I remember it was as loud as the camera shutter noise, once I was shooting a baby the focus engine sound woke him up.No more problems in low light than I have with other f2.8 lenses.

The lens is very sharp even at f2.8 contrast is nice, sometimes you have the typical sigma yellow, but this is nothing to worry about.



Its cons: big and heavy, 82mm expensive filters, it has a focus clutch=two buttons to push when going from AF to MF, fragile: I broke two of this lens into pieces, but I don't think this will happen to you, just don't drop it.



all in all, I think optically it is as good as Canon 24-70L, just make sure you have a good sample, there are some mechanical shortcomings, but you can live with them <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />