DSLR Photography Forum

Its official.... I'm in love with fast primes!
Well, that's not really breaking news.. I'm sure the gazillions of people out there with a decent 50mm f/1.x lens on any camera system will have some idea of what the feeling is like. And those who own something like an EF 85mm f/1.2L or EF 200mm f/1.8L will be silently smiling and nodding as they lovingly caress their lens.
Now, all I need is for fast primes to love me back!

I just ordered myself a "Sigma Wide Angle 28mm f/1.8 EX Aspherical DG DF Macro" which is a very flowery name for a lens that isn't really a wide angle (on a 1.6 crop factor camera) or really a macro (1:2.9 reproduction ratio), but is most certainly a very useful fast prime.

http://www.sigmaphoto.com/lenses/lenses_...avigator=4

There seems to be a plethora of choices for fast primes in this kind of focal length for Canon... 20mm, 24mm, 28mm, 30mm, 35mm... ranging from f/1.4 through to f/2.8, macro and not.
My needs were fairly simple - I wanted something close-ish to what a normal 50mm lens would be on a FF camera or a touch wider (28 x 1.6 = 45mm), good optics, must be fast (f/2 or faster), well built (better built than the EF 50mm f/1.8), and affordable (Canon's L glass was out).

In the end it came down to the Canon 28mm f/1.8, and four(!) Sigmas - the 20mm f/1.8, 24mm f/1.8, 28mm f/1.8, and 30mm f/1.4.
It seems that apart from the 30mm f/1,4 which is quite a different beastie (and APS-C only), all the other lenses appear quite similar in terms of optical quality and build quality based on opinions and reviews. All would be suitable for my needs (perhaps the 20mm and 30mm were starting to get away from the focal length I wanted).

In the end the deciding factor simply came down to price. The Canon 28mm and the Sigma 20mm and 30mm were all about the same price (US$399), but the 24mm and 28mm were considerably cheaper (US$319 and US$249). Considering 24mm or 28mm were my preferred focal length anyway and there was so little between them, I was quite happy to go for the Sigma 28mm and save a few bucks to put towards my 30D.

The Canon would have given me faster autofocus I suspect which would be handy (it is USM, but not particularly fast apparently), but AF speed isn't as much of an issue with wider lenses as telephotos and I'm hoping the Sigma will still be up to the task. It didn't seem worth a 60% price increase to address a problem that may not exist in the Sigma or if it does then it may not be solved by the Canon (but I may live to curse this statement).
The so-called macro ability of the Sigma also appealled to me - its closest focus distance is 20cm (from the sensor) which ends up being under 5cm from the end of the lens. Nothing groundbreaking or even macro in the true sense, but still very handy.

But the proof will be in the pudding. It should get here in a week I guess.
I'm suprised how little there seems to be on the net about any of these lenses. I guess primes in this focal length range just aren't sexy, while ultra-wides and long telephotos are.

I'll no doubt post some pix when it arrives. As if I wouldn't!

Wow, I'm excited for you! Sounds like a pretty cool lens - wider than a fifty, and fast optics too.

Haha, shall we start that debate about the standard lens again?

haha.. yeah Jules lets start that again!

Actually, it wasn't until after I'd decided on this focal length that I remembered that thread.. and sure enough there is a reference in there to a luminous-landscape essay suggesting that 28mm is an appropriate "normal length" for 1.6x crop factor cameras.

But that's not how or why I chose it. I'm more interested in a "useful length" than a "normal length".
While choosing this lens I developed a very un-scientific and non-technical method for choosing focal lengths for lenses:
1. Pick a shoot I've done in the past which is appropriate to how I intend to use the lens (ie sports, landscapes)
2. Make sure I've used a wide variety of focal lengths in the shoot (and used them to the best of my ability).
3. Pick my favourites from the shoot that could be improved slightly, or my "would-be favourites" (ie shots that might have been good had I been able to get a wider aperture, or a slightly different focal length, or a macro shot, or IS, or whatever lens feature it needs).
4. See if there's a common focal length among those shots, or some kind of pattern.
5. Repeat the process for another shoot until I get a feel for where the gaps are appearing.

Just common sense? :/ I guess we'll see how useful the lens proves itself to be.

Well the lens arrived this week!
I've had a couple of days to play with it and take a few shots, but haven't gone out for a proper days shooting with it yet so these are very much just my initial thoughts.

Overall I'm happy with it, but with reservations. It has a number of quirks which are mildly annoying but I'll get used to and forget about soon (such as the bizarre manual focus mechanism), one or two noticable weaknesses (the auto focus mechanism), but also some wonderful strengths (fantastic detail, colour, DOF, bokeh, and so-called "macro" ability).
I haven't done any scientific tests on it (and don't intend to).. and seeing as I don't have any children I have been chasing my cats around to shoot instead!

Here are some thoughts in no particular order:
1. It's big! Way bigger than the Canon 28mm f/1.8 equivalent, the Sigma lens is almost exactly the same size and weight as my Sigma 10-20mm zoom, and also takes the same 77mm filters. It is significantly bigger than the 350D kit lens or EF 50mm f/1.8... and much better built than either of these two lenses as well (same great build quality as the Sigma 10-20mm).

2. Autofocus is yuk! The autofocus is not HSM, and it feels very slow and is LOUD. Half the focus sweep range is in the 4-30cm range, and this is one lens that would really benefit from the little button found on a number of Canon L-lenses that restrict auto-focus to the far half of its range in order to double the focus hunting speed. Once it has locked on to a target the Sigma seems to track it nice and quickly (I think - haven't tested it with sports yet though), but if it loses its target and it has to hunt through the whole focus range then it is frustratingly slow. The focus noise level normally doesn't bother me much on lenses, but this is by far the noisiest lens I own, which is annoying seeing as its also the closest thing I have to a macro lens... How am I going to shoot insects when it scares my cats away!

3. Its quirky! I don't know if it is just because of the strange 2-stage manual focus mechanism, but although it shares the same build quality as the Sigma 10-20mm zoom, it feels like the (non-optical) engineering in this lens is years behind the 10-20! It feels slower, noisier, clunkier, and just much much older than the 10-20 zoom. It feels like a lens that was designed 30 years ago.
And guess what... although these things might be considered faults, its kinda cool! I like it when inanimate objects take on a personality (like my kombi), and this lens feels like it has one. I get the feeling it is the kind of lens you don't just use; but rather you have a relationship with it.

4. And finally, the image quality. Well I think in general it ranges from "great" to "breathtaking". When glancing at real-world shots (not test charts) the best shots from this lens are right up there beside the best shots from my 50mm f/1.8 and 135mm f/2L in terms of sharpness, detail and colour. The Bokeh is softer and more natural looking than the 50mm f/1.8 and more like my 135 f/2L. But I quite like the distinct bokeh of the 50mm f/1.8, so this is neither a good or a bad thing.
It seems fairly resistant to flare, but when it does appear it seems to show up pretty badly. It doesn't seem quite as contrasty as my 135mm f/2L, but it does seem to capture an amazing amount of detail and subtlety in the mid-tones.
And then when I took it outside today in the late afternoon with a polarising filter for the first time - I was simply blown away by the colours. Stunning.

Anyway, enough guff. I know people aren't all that interested in this lens anyway.. and a picture tells a thousand words. So here are just a few of the sample shots I've taken in the last couple of days. Hopefully I'll go out and shoot some "proper" shots instead of just shooting my cats around the house.


1. Rocket was wondering why the lens sounds like a power-drill when its focusing.
200 ISO, f/2.8, 1/250th sec (with polariser)


2. This lens with a polariser was giving Rocket and the sky gorgeous colours in the late sun.
200 ISO, f/2.8, 1/180th sec (with polariser)


3. Great for available-light shooting - this was hand-held in very dim light.
800 ISO, f/1.8, 1/30th sec


4. While not a real macro lens, Danni helps demonstrate that this lens does focus in quite close which is handy.
800 ISO, f/1.8, 1/500th sec


5. 28mm is a really handy focal length on a 1.6 crop camera as well. I'm finding it a lot easier to frame many things than my 50mm. Mind you, I've been mainly shooting cats with this lens, so its not really a broad test.
200 ISO, f/1.8, 1/1000th sec


6. I posted this composite of 3 shots in this thread, but it is another good example from this lens from today so I'm including it here too.
200 ISO, f/2.5, 1/180th sec

The new lens looks great Kombi. The shot of rocket in the sun is fantastic, colour, detail and sharpness!!

Your cats on the wall is excellent!!! very cool

PS just looked again the first shot shows rocket's character.........gotta be the most photogenic cat on the net

The shots are great! as to be expected, coming from you.

I notice the combination of an unusually wide angle in combination with the 4x6 sensor format though, you'll have to get that frame filled!

looks like lots of fun!

uli

I see there aren't many that have this lens or are interested in it. Man was I glad when I came across this "review"!
I'm currently in the same exact situation that you were in. I need a cheap, fast lens close to 50mm on a FF.

This Sigma 28 f/1.8 immediately caught my attention for the ridiculously low price. I'm struggling to make the decision on the Sigma over the Canon 28 f/1.8 because I keep seeing some AF issues with the Sigma. At f/1.8, some focusing issues could go a really long way.

I don't really care for slow focusing speed, but can you compare it to the kit lens? I find the kit lens fast enough for what I shoot with it. But when I throw on a USM lens, it's a different story. The focusing noise doesn't bother me much either. It almost brings the lens to life like it's talking to you.

Your input would be greatly appreciated.
Thanks,
Chris

Thanks Russ and Uli.. I agree that Rocket is the most photogenic cat on the net

Sorry for the late reply Chris, this post slipped past unnoticed.

As far as comparing the AF speed to the kit lens.. it is a bit slower when hunting for focus (where it goes through the entire focus range) but faster when it doesn't have to hunt. It is also considerably noisier than the kit lens.

I performed two unscientific tests comparing the AF speed of the Sigma lens to the EF-S 18-55 350D kit lens and also EF 50mm f/1.8 II. I didn't use anything to measure these speeds, just a partially-working brain.

The first test was simply mounting the lens on the camera with the lens cap on and then trying to lock focus. It sweeps through the entire focus range and obviously can't lock focus in pitch black darkness. In this test the kit lens was the fastest, followed closely by the 50mm f/1.8 with the Sigma lagging behind. The difference wasn't massive, but it was noticable.

The second test involved switching the camera to AI Servo focus (ie continuous AF), holding my hand at full reach in front of the camera, letting it focus on my hand, and then moving my hand out of the way and seeing how long it took to change its focus onto some detail on the wall behind my hand. In this case the Sigma won, followed by the kit lens and finally the 50mm. Again, the differences weren't massive but they was noticable - in the Sigma's favour this time.

The reason for this seemingly strange result is the fact the Sigma will focus much closer than the kit lens; half the "sweep" of the AF rotation accounts for focusing within the closest 10cm of the focus range (which is beyond the closest focus point of both the kit lens and the 50mm). During normal shooting it doesn't need to go into this range, but when it hunts it does.

As far as manual focus goes, apart from the quirky push-pull switch to activate manual focus on the Sigma, it feels much nicer when turning the manual focus ring.
I also suspect a touch of front-focusing on my copy of this lens. I haven't done any real tests to investigate this, but when shooting wide open I seem to consistently get the point of focus just a bit ahead of where I intended it to be. It might just be me though.

I hope that helps you with your decision. Overall it is a nice lens that is dragged down a bit by its AF performance. Just the fact I'm comparing this lens to the kit lens and 50mm f/1.8 II when it comes to AF performance is bit of a bad sign.