Do I even need a 30/1.4 or 28/1.8 prime?

I was considering the Sigma 30mm f/1.4 and Canon 28mm f/1.8 as a lens for shooting an upcoming indoor event (not low light, just indoors), under the possibly false/outdated assumption that good primes outperform zooms. But now that I've actually read reviews and seen tests of these lenses, I have to wonder if either of them is really worth the ~$500, or if I should just rely on my trusty 17-55mm to get the job done.

Specifically, I'm noticing that review sites the the-digital-picture and photozone.de don't actually think too highly of these primes, and to my surprise, they both appear to benchmark more poorly than the 17-55 zoom in terms of sharpness and CA. As one expects, they exhibit less distortion than the zoom lens, but with ACR's automatic correction, that's a total non-issue for me.

So my question is: if I'm not working in low light (certainly not low enough where I couldn't focus the f/2.8 lens) and I'm not interested in super shallow DoF shots, is there any reason whatsoever to consider using one of the standard prime lenses over the 17-55 zoom?

I think you've pretty much answered it yourself here. Stick with what you have and see how that goes. It all comes down to what style of indoor photography you want to do.

If you don't need it, don't spend money on it.

However, don't read too much into those reviews. It doesn't necessarily represent how things work in real life, e.g. because of supposedly soft corner, the 30 /1.4 is rated two stars on photozone, however in real life for portrait shots, it's pretty much a non-factor to me at all.

Well I have the Sigma 30 f1.4 and the 17-55 f2.8. The Sigma comes out in low light such as clubs or when I want to do more creative blurred background type of things and yes I love the lens. But at an event I'd choose the 17-55 every time because of the versatility of the zoom and you still have 2.8. It's hard (for me anyway) to get people pictures at an event and keep them reasonably in focus at less than 2.8 anyway.

If you can shoot at f2.8 or f4 and get high enough shutter speeds, you certainly don't "need" a fast lens.
If lighting is good, you may be able to do it with the zoom.
I have the 35f2 and my lens is very sharp across the frame. The SLR gear review is more like the lens that I have.
The Photozene comments, if I recall correctly, had to do with bokeh at smaller apertures. In my experience, the 35f2 is a good lens. The Sigma 30f1.4 may show some copy variation, since the SLR gear review is much more positive than some other reviews that I have read.
No, you don't need an f2 lens if you know that the light is sufficient for f2.8 or smaller apertures.

absplastic wrote in post #12893411
I have to wonder if either of them is really worth the ~$500

I don't think you need either of them since you're shooting in environments where 2.8 is enough. However, I'm going to say this:

If my sigma 30 1.4 died, I'd buy another one. If that one died, I'd still buy another one. I like it that much.

Thanks everyone. When I went looking for a prime in the 28 to 35mm range, I was only doing so with the expectation that I'd get both better AF indoors and significantly better sharpness from a prime. While it's definitely true that my 60mm prime outresolves my 17-55, I was actually surprised to see that even in Canon's MTF charts that the 28mm f/1.8 is not outperforming the zoom. I guess I just needed to revisit the zoom vs prime issue, which I honestly haven't done seriously since I first got into photography some 20 years ago. The technology in zoom lenses has clearly improved!

Saves me $500

Depends on the lens honestly

I will say the Sigma 30 f/1.4 is one of the sharpest lenses I've ever owned and it made my jaw drop with how breathtakingly stupifyingly sharp it is at about f/2.8-4.....

Wide open it wasnt a slouch either, and my Sigma 50 is certainly one of the best lenses I've used as well.....

Usually however the bigger reason to have a prime is that primes usually START at f/2.8 and get faster, Zooms can only ever go to f/2.8 due to size limitations....

As said before, don't pay too much attention to those MTF charts, et cetera, they don't really give you an idea of how a lens performs in practice, according to those pretty charts, my Sigma 24mm F1.8 should be completely unuseable wide open, but guess what, it's not.
And also, as KenjiS said, the real reason to have primes IS the fact that they tend to have far larger apertures than zooms ever will... however if you do have enough light to use your 17-55 F2.8, don't bother with buying more lenses just for that event. Primes are great, but if you're used to zooms, then switching to primes can be a pain in the arse(especially if for just one event), and in the end you'd probably get better results with a zoom lens.

Tony_Stark wrote in post #12893477
I think you've pretty much answered it yourself here. Stick with what you have and see how that goes. It all comes down to what style of indoor photography you want to do.

Right on.

It's not just about IQ... The primes and your zoom are probably about equal in that respect. The primes you mention are good, but your zoom is exceptionally good for a zoom.

The difference is that one of the primes is two full stops faster than your zoom, even though it's fast for a zoom. The other prime is 1.3 stops faster.

Another difference is that the 28/1.8 for example, is a lot smaller than your zoom.

Anotther is that your zoom cost more than twice as much.

Of course, your zoom covers a wide range of focal lengths and does it very well for a zoom.

Your 60D can easily shoot ISO 1600 and maybe even 3200. Between that and the fact that your zoom has I.S., you can probably handle most situations with it.

Sirrith wrote in post #12893912
If my sigma 30 1.4 died, I'd buy another one. If that one died, I'd still buy another one. I like it that much.

I felt it the same way before I bought the 5D. Really it's still my favorite, sometimes I want to buy it back!!! But I don't shoot 60D much anymore, it doesn't make sense to get it back.

absplastic wrote in post #12893411
I was considering the Sigma 30mm f/1.4 and Canon 28mm f/1.8 as a lens for shooting an upcoming indoor event (not low light, just indoors), under the possibly false/outdated assumption that good primes outperform zooms. But now that I've actually read reviews and seen tests of these lenses, I have to wonder if either of them is really worth the ~$500, or if I should just rely on my trusty 17-55mm to get the job done.

Specifically, I'm noticing that review sites the the-digital-picture and photozone.de don't actually think too highly of these primes, and to my surprise, they both appear to benchmark more poorly than the 17-55 zoom in terms of sharpness and CA. As one expects, they exhibit less distortion than the zoom lens, but with ACR's automatic correction, that's a total non-issue for me.

So my question is: if I'm not working in low light (certainly not low enough where I couldn't focus the f/2.8 lens) and I'm not interested in super shallow DoF shots, is there any reason whatsoever to consider using one of the standard prime lenses over the 17-55 zoom?

I have the Sigma 30mm; like its bokeh and low-light capability. Not sure about sharpness, never tested it against my other lenses, they all seem fine. Sharpness is a non-issue with virtually any modern lens.

https://photography-on-the.net …=1067589&highli​ght=colbie

a few i recently shot at a concert.

Use what ever you have allready saved to get your macro lens.
That will give you more extras than the prime.