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Review: Sigma 85mm f/1.4 DG EX HSM
The Sigma 85mm f/1.4 DG EX HSM is a super fast aperture, short telephoto lens. This is a new design for full-frame (and DX) sensors from Sigma, incorporating the Hyper Sonic Motor (HSM) found in the rest of their EX range of lenses.
There is a lot of debate amongst photographers these days as to whether there is a real need for a fast f/1.4 aperture lens in modern photography.
On the one hand people are saying that with modern sensors like those found in top end Nikon bodies such as the D3-series, D700 and now D7000, you’re able to shoot at ISO values that were previously unworkable, such as 3200 and even 12,800 in the case of the D3S. Why then would you need to claw back 2 stops in aperture terms and lose massively on depth of field? Not to mention the huge premium you will be paying for glass that does that?
On the other hand those photographers who use fast aperture lenses are saying that the super fast 1.4 apertures bring something visually unique to the table – total subject isolation and smooth out of focus areas. Not to mention the fact that in low light situations these kinds of lenses really do bring about a whole new dimension to photography because now not only do you have the extra stops on your sensor, but you also have them on your lens, and when used in conjunction with one another they make for compelling photography in difficult lighting situations.
I tend to agree with the latter argument, but at the same time I look at each lens I own as being something that has to carry a fair share of the workload to justify its existence in my line up. I don’t want to spend a lot of money on a lens that I am seldom going to use.
For me the super fast lenses are all about depth of field and how you can use that creatively, so if I am going to carry a lens like this, I want to be able to use it for its ability to shorten the d.o.f. in generous dollops. This 85mm 1.4 does that pretty handily.
This is very much a specialist lens and finding work for it is going to depend to a large degree of the kind of photographic intent you have. Personally I find this focal length difficult to work with because it doesn’t quite fit my style of working. The minimum focusing distance of 0.85m is a bit too long to get in close to smaller subjects, such as food and small products where its shallow depth of field would work well. However, on a DX frame that might not be as much of a problem and DX shooters might very well consider this lens for use in food photography, especially where your only light is ambient and you’re doing selective focus on parts of the dish. It will work very well there.
Conventional thinkers all agree that 85mm on FX is the beginning of classic portraiture focal length. If I am shooting head and shoulders type portraits using this lens I find I am standing a little bit too close to the subject for my liking (like 1 to 1.2m from their faces). It’s not that I have halitosis or bad BO or anything, but getting that close to somebody’s face for a photograph puts me on the inside of their personal space where I will run the risk of unsettling them, something that always comes through in the pictures.
Having said that, if you are using this lens to make that kind of portrait, you must understand two things:
1.This is a very sharp lens at any aperture so every line and wrinkle in that person’s face is going to stand out.
2.If you open this lens wider than 2.8 your depth of field is going to be so shallow that you may find only a small section of the subject’s face will be in focus. It’s quite possible to have the tip of a nose sharp and the eyes out of focus when using the lens at f/2 or wider, especially when you’re working up close with the subject. Make sure you focus on the right part of the face if you’re aiming for a shallow depth of field!
The shot of a ruler below (this is a significant crop, btw) shows just how limited your depth of field is when shooting at f/1.4 and the minimum focusing distance of 85cm with this lens.
I wouldn’t recommend a lens like this for portraiture simply on the basis of the working distance on FX format, as well as the sharpness issue. It’s too sharp for flattery, which in most cases is what you get asked to do when making portraits. This might be fine if you’re doing some kind of reportage journalism and you don’t have to explain yourself to the subject later, but trust me, if you’re formally photographing women of a more mature age, you’re going to pick up flak!
Anyway, you’re not reading this review to make a decision on what type of photography you should be doing with an 85mm f/1.4, so on the next page I will get into the performance aspects that will help you decide whether or not to buy this lens.