Which wide angle to choose ?

[chris-p]

Originally Posted by Mad as a fruitbat

buying the sigma would allow me to buy some other equipment !

Especially if you go for the cheaper f/4-5.6 model, rather than the pointless f/3.5 version.

Originally Posted by gtirman

I have used the Sigma and it is great but dont overlook the the Tokina 11-16 which is the one i have. Crystal clear pics.
You cant go wrong with either.

The only caveat I would add to this is that, although 1mm doesn't sound a lot, at the wideangle end it can make quite a difference to the field of view.

For example... I've calculated the field of view for 10mm and 11mm on a Nikon D300 with the lens focused at just 10m.

@ 10mm the FoV is 110.5 degrees which means you're covering and area (with the lens focused at 10m) of 24m wide and 16m high.

@11mm the FoV is 105.3 degrees which means you're covering and area (with the lens focused at 10m) of 21.8m wide and 14.5m high.

This is mostly academic, but it's worth knowing that the relationship between focal length and FoV is non-linear. In other words, the shorter the focal length gets, the more of a difference each mm makes to your focal length.
Of course, the wider the angle, the more curvilinear distortion you get but it's expected with these lenses and you can work around it very easily if you get to know the lens properly.

[James Blonde]

I just bought the Sigma 10-20 F4-5.6 (rather than the newer F3.5) from Amazon for about £350, rather than the more usual £400 I'd seen it for elsewhere, and a lot cheaper than the newer lens. The other benefit is that the filter size on the F4 is 77mm, rather than 82mm (I think) on the newer lens.

I have to admit, its so new I've not had a chance to use it yet!

[chris-p]

Originally Posted by James Blonde

I just bought the Sigma 10-20 F4-5.6 (rather than the newer F3.5) from Amazon for about £350, rather than the more usual £400 I'd seen it for elsewhere, and a lot cheaper than the newer lens. The other benefit is that the filter size on the F4 is 77mm, rather than 82mm (I think) on the newer lens.

I have to admit, its so new I've not had a chance to use it yet!

Good choice.

The smaller filter size does help with the f/4-5.6 lens but the main reason I suggest the f/5.6 over the f/3.5 is because there is nothing to be gained from the slightly faster aperture on this type of lens.

I look at it like this: brighter apertures allow you to shoot either faster or shallower (or both). These lenses (all of them, not just the Sigma) are primarily aimed at landscapers. Shallow depth of field is rarely a good thing for landscapes and f/3.5 at 10mm is hardly shallow.

If you calculate it, a 10mm focal length on an APS-C sensor at f/3.5 has to be focused on something closer than 1.5 metres away to get anything less than infinite depth of field (focused at 1.51m, DoF is 163 metres, focused at 1.51 metres away it's over 600 metres).

Alternatively, you think brighter lens = better in low light. Most landscape photographers who are serious about low light landscapes will have a tripod and will also often require a smaller aperture if they want starlight effects. Couple this with the fact that f/3.5 isn't particularly bright anyway and you don't really gain anything here either.

In short, you don't get either of the main factors you would normally buy a faster lens for. You won't get shallow DoF unless your focus distance is very short and you won't get significantly faster shutter speeds for hand held shooting.

[Mad as a fruitbat]

Thanks for all the replies and advice, yesterday I went and bought the sigma (along with with some other stuff I just had to have). Looking forward to getting out there with it now !

Cheers

[rbarry]

Great advice from Chris for you Mad. I'm in a similar position wanting a wide angle lens to use with a Canon 550D. I may not have thought that hard about it, but I totally understand Chris's reasoning for recommending the earlier "slower" lens and appreciate his advice.
There is little advantage to be had in having a fast wide angle lens; the lens you choose should be fit for purpose, and it seems the earlier Sigma is not just a great choice, but also the better vfm.

[Mad as a fruitbat]

Having decided to buy the Sigma 10 - 20 4 - 5.6, I then used the £250 saved to put towards the nikon close up flash system I had been looking at

[chris-p]

Originally Posted by rbarry

Great advice from Chris for you Mad. I'm in a similar position wanting a wide angle lens to use with a Canon 550D. I may not have thought that hard about it, but I totally understand Chris's reasoning for recommending the earlier "slower" lens and appreciate his advice.
There is little advantage to be had in having a fast wide angle lens; the lens you choose should be fit for purpose, and it seems the earlier Sigma is not just a great choice, but also the better vfm.

I've lost count of the number of times I've extolled the virtues of the 4-5.6 lens. It's a big difference in cash and I'm glad it's helped people.

Just to be fair, I would say that a fast weidangle lens can be brilliant. It's just that f/3.5 isn't fast! Something in the region of f/2 to f/2.8 would actually be worth the investment.
It would really be an investment though - the Nikon 14-24mm f/2.8 is still £1300 and a real stormer of a lens on a full frame camera where 14mm is VERY wide!

[ap4a]

F/3.5 is more than a stop faster than f/5.6, that's well worth having. If all you ever do is shoot from a tripod then it won't make much of a difference, but a lot of people shoot hand held and can't always rely on a flash.

FWIW I have the F/4-5.6 version but wouldn't write off the F/3.5.

[Muckyboy]

Thanks guys - this is just what I wanted to know!

Having just replaced my 18-55 kit lens with the Sigma 18-50 f2.8 and being amazed at the difference in quality it gives,my next target was going to be a wide angle for some landscape work.

Looks like the Sigma is the one for me!!!