If you're expecting charts, scientific stuff or photos of brick walls, go somewhere else; I don't shoot them in real world scenarios, so there's not going to be any here for a write up on a lens...
People who know me will say that I have a lot of love for Sigma lenses, I've had a few in my equipment bag since I went digital and each time I go for a new lens the odds on it being a Sigma become greater especially as Sigma make some "oddball" lenses that are outside of other manufacturer's comfort zones (but definitely in mine, like that 24-35 for one!).
This post here, it requires a little background to lenses that have come and (some have) gone before to understand where we are up to now.
When I moved to digital, I was never happy with the 1.5 aspect ratio through a "full frame" lens, and as the Nikon were at this time only crop sensors nothing felt right and the wide stuff always felt too close to 50mm for my liking (a length I've never really got on with as an all rounder, finding it too narrow or too wide) and the only fast in the mid/wide on crop that wouldn't give me that feel was the Nikkor 17-55 F:/2.8 so I'd resigned myself to one of them.
However, when I went to buy the Nikkor lens, the dealer didn't have a stock and wouldn't do for a few months, and I ended up picking up the Sigma 17-70 F:/2.8-4.5 DC as a stopgap and ended up treating that as a constant F:/4... Now this was where it got interesting as I'd used this lens for the few months and found that I preferred the range on it and whilst it was a stop slower than the Nikkor I found that I wasn't going to F:/2.8 at the widest nor was I missing it. The Sigma fitted better to my work than where I thought it would have.
That was ten years ago and I still didn't get the Nikkor; and in the intervening years that Sigma has been on at least three different crop bodies, it is still in use in my fun stuff on the lightning camera but I'd gone over to full frame. Initially I was back on the Nikkor 28-70 F:/2.8 but that lens whilst good it never filled me with that happy feeling and was always like fighting an angry cat to get what I personally wanted from it in the situations I worked in; and I found I was stepping it down to get it to be "good" (then it still wasn't that spectacular), so it was a very heavy, limited F:/4 - F:/5.6 of short focal length and it's sharpness even on a D700 (so only 12mp compared to the big sensors of now) seemed a bit not there.
In clean light, it was great, and up at F:/8 - F:/11 really sharp, but either I was looking back at it with rose tinted glasses and it was never the lens I thought it was or there was something else underlying that I'd not noticed before. After a shoot on a beach, it started giving me hassles due to sand in the mechanism, so I persevered with it but the aperture seemed to be getting more and more approximate with each month that passed so in the end I went to look for something else and something more "me".
That journey took me through a couple of lenses that I found either too brittle or just so so when it came to things, and then after going round all the houses, I was back to the Sigmas... And the 24-105 F:/4 Art.
I know this lens is now three years "out there" but after trying a few over the years, I already knew it was a matter of when not if one of these found it's way in to my roster of lenses. And it did.
So is it a gigging lens? If folk all around the internet are to be believed, no as it's not a fast prime... There's a running thing for the last few years that every year I'll get I don't know how many people telling me that I'm doing my stuff wrong (either with Autoput or other bands/organisations I've worked with) because I'm not using a fixed focal length massive aperture thing. It's become a bit like bingo, but if I went through and had a look at all the stuff of mine that's made it in to print, on to posters, album covers, t-shirts, publicity materials, and whatever else I think that in all of it there has only ever been one photo (without checking, there may be 2 or three, but not more than what I can count on the strings of a Fender Precision Bass) that has got there on a fixed focal length, wide aperture lens! All the other stuff has been on things tighter than F:/2.8, on zoom lenses.
And back to the Sigma, does this fit in to the line up? After shooting a few shows with it, and having to get used to how incredibly bright it seems compared to other lenses I've used at comparative apertures and getting my head round having more range on the shutter speed and / or aperture with what I was used to, and also having that extra nearly 40mm back at the top end (as well as the rather impressive vibration reduction and AF on it) I've not had it off the front of the lens for the last few shows; and one of them was with the worst lighting rig I'd have ever worked with.
It's an incredible performer, sure it does flare a bit (usually when provoked with stage scum or humidity on the front element) and sometimes the AF fails to track properly (but I'd say that's about equal to any other lens I've used, and compounded by odd lighting patterns and perhaps more down to the limit of the AF sensor in the camera) however it's like a razor and the images seem to be as good on this when post processed (which involves a bit of noise reduction, so sharpness does bail a bit) at really high ISO settings where the other lenses I have would look rather smooth and "polished" at that similar setting with the same aperture.
Colour and contrast, these are really, really something else, as even when provoked under nasty it's not losing a lot if any; the only time I found it does struggle is if there is Puff the Magic Dragon (smoke cannon) has a red light up it's bum and is punching heavily... Then things seem to get a little washed out, but in a normal situation if there's a breeze that's a situation I personally wouldn't encounter a lot. Just because of these and the sharpness, there's a lot less work on a lot less photos in the post show hours and I'm finding the difficult part now is what not to send in as subs because the shot to keep ratio has increased no end.
I'm really finding it to be a breath of fresh air, and from a working perspective I've not found anything to grumble about, the balance is good, the construction is exemplary, the mechanisms damped beautifully with just the right amount of force needed to make things happen, and if there was one thing I've found it's the focal length marks and that's it. I sweat quite a bit and it's rather corrosive as well (as the paint work on my battery grips or the palm rests on my Macbook Pros would attest) and that's starting to fade off a bit from where I hold the thumb on to the lens. However that's rather insignificant for a lens that isn't going to be sold on and I don't use them anyway because the eye is in the finder!
In all, I'm loving this lens and kicking myself for not picking one up a few years ago; from someone who uses it in the field and really drives the kit hard, this lens is one of them beasts that delivers and delivers well.
The other night (where the photos in this post were from) I only took two lenses out there, instead of the usual five, there was this and the Sigma 70-200, and the covers didn't come off that all night.
All in, finding a lens I'm satisfied with is a hard thing, but this checks the boxes pretty much in all respects for me; and from the Sigmas of really old (and I mean a fair few years ago) if this here is a yardstick on to where they are now, they are really starting to make a lot of OEM stuff look backwards and dated.
Now I've had hands on with this, I can't wait to spend a few days with that new 24-70 F:/2.8 as whilst it's not something that would suit my working style with the shorter focal length, I wouldn't be foolish to raise a bet against it.