Sigma 30mm f1,4 vs. Canon 28mm f2,8

[henrik.ploug]

Here are some test shots from the Sigma 30mm f1,4 and the Canon 28mm

f2,8. None of the shots have been sharpened in camera or in Photoshop.

 

The Sigma is sharper in the center and the Canon is sharper in the

corner, when compared at equal apartures.

 

The center sharpness of the Sigma at f1,4 can be compared with the

center sharpness of the Canon at f4. The corner sharpness of the

Canon at f4 can be compared to the Sigma at 5,6.

 

Both lenses show some vignetting when used wide open. The vignetting

disappear, when you stop the lenses down one stop.

[bellavance]

Henrik,

 

I guess this was done with your 350D.

 

Corner performance of the Sigma lens is less than impressive. I wonder how it compares with the Canon 28/1.8 lens?

 

Pierre

[henrik.ploug]

Yes it's done with my 350D - sorry, I didn't mention. And you're right, the corners are pretty soft. But the center is sharp wide open, so I guess it depends on what you intend to use it for.

[bellavance]

I guess corner performance is probably good enough. I was hesitating between the Sigma 30/1.4 and the not too stellar Canon 28/1.8 lens.

 

What worries me is that Canon is talking a lot of full frame sensors these days...

 

http://web.canon.jp/Imaging/cmos/index-e.html

 

Pierre

[steve_dunn2]

<p>The future of 1.6-crop and full-frame sensors in the EOS DSLR lineup is a concern for one's lens collection in general. Even if you decide to stick with full-frame lenses, you still have to tailor your lens collection to your needs, and it's a bit hard and rather expensive to do that if you're trying to build one lens collection which serves your needs with both 1.6-crop and full-frame bodies. For instance, if you decide to purchase (say) the 28/2.8 as a (roughly) 50mm-equivalent lens for a 1.6-crop body, then you upgrade to a full-frame body, the fact that your 28/2.8 is a full-frame lens doesn't fix the fact that it's no longer a 50mm-equivalent lens. Unless you need a wide-angle prime, you're going to end up selling it and buying a 50. Ditto for the Sigma; the question there is whether the market for 1.6-crop lenses will remain strong enough for you to get a reasonable price for it.</p>

 

<p>This is purely speculation, but my guess is that Canon will be selling 1.6-crop bodies well past 2010. I fully expect the 20D's successor to be 1.6-crop, and I expect that body to come out early in 2006. The one after that, probably in late 2007, may be 1.6-crop or full-frame, depending on the cost of a full-frame sensor, but at this point, my guess would be 1.6-crop. So maybe in 2009 or so, the advanced-amateur body could get a full-frame sensor. But everything below it will still be on 1.6-crop for at least a year or two after that; even entry-level DSLRs these days still command a fairly steep price, compared to entry-level 35mm SLRs, and even if there's a full-frame Digital Rebel around 2010 or 2011, I expect to see 1.6-crop remain past then to hit a lower price point. And of course there will still be a market for used 1.6-crop DSLRs for those who don't need or can't afford full-frame. So I think there will be a market for used 1.6-crop lenses, too.</p>

 

<p>Anyway, that's just my speculation, and I've been wrong before :-)</p>

[athinkle]

If the edges are soft even on a 1.6 body, that's a very bad sign for anyone wishing to use the lens on a FF or 35mm body. I always felt that the nice thing about 1.6 bodies was the removal of vignetting and corner softening from fast lenses. Oh well.

[henrik.ploug]

I have paid about 1000$ for a camera (350D), that I know, will be obsolete in about three years. So a 500$ lens is not that big a deal. I guess it's just the name of the game, untill 25 megapixel full frame censors are a part of every consumer DSLR.

 

Of course it's a lot of money right now. But let's say I can get one third of the price for the lens and the camera in three years. Then I would have lost 1000$, which is about 28$ a month. I don't think that's too much money for a hobby, that I enjoy very much.

[henrik.ploug]

Andrew, the Sigma 30mm f1,4 is for 1,6 crop cameras only.

[henrik.ploug]

I have just expanded the test, so that it now also includes an edge crop. At the upper edge the two lenses seem to be equal, and both lenses are quite sharp wide open.

[bellavance]

This is interesting. Would you try the left (top or bottom) corner just in case there would be a problem in the right corner?

 

Thanks

 

Pierre

[henrik.ploug]

I'll be back!

[henrik.ploug]

Here we go! The sharpness in the left corner is the same as in the right. It's a bit harder to see, but if you look at the two dark lines at the bottom of the window, it becomes apparent. Again the Canon is a bit sharper than the Sigma at equal apartures.

[bellavance]

Henrik,

 

On the left side pictures, at equal aperture, the Sigma looks sharper to me, or seems to have more contrast.

 

Thanks for your help.

 

Pierre

[henrik.ploug]

I don't agree. If you look at the pictures taken at f2,8 (in the left corner), the Canon is a little darker, but that is because of the vignetting. At f4 I think it is very clear, that the Canon is sharper.

 

So my conclusion is, that I must avoid getting the motif stuck in the corner, when I shoot with the Sigma. And that the Canon will soon appear on eBay.

[bellavance]

You're right. I had them mixed because the Sigma lettering is above the Canon lettering while its image is below Canon's...

 

From the two horizontal lines, we see they only get even at f/8

 

So, do you agree that center and edge go to Sigma, and corners go to Canon?

 

Pierre

[henrik.ploug]

I think they're about equal at the edge. But Sigmas two stop advantage does it for me.

[yakim_peled1]

Both lenses are very good but for me, the combination of price, full future compatibility and FF compatibility tilt the scale to the Canon 28/2.8. Amazing performance from such an ancient design.

 

Then again, my 35/2 and 24/2.8 are also old design and perform excellently so I shouldn't be so surprised. Prime lenses rule! :-)

 

 

Happy shooting,

Yakim.

[henrik.ploug]

I have just added crops of the left edge, and again it is difficult to find a winner. But I think the Canon is a little better.

[kin_lau]

Steve Dunn said: "For instance, if you decide to purchase (say) the 28/2.8 as a (roughly) 50mm-equivalent lens for a 1.6-crop body, then you upgrade to a full-frame body, the fact that your 28/2.8 is a full-frame lens doesn't fix the fact that it's no longer a 50mm-equivalent lens. Unless you need a wide-angle prime, you're going to end up selling it and buying a 50. Ditto for the Sigma; the question there is whether the market for 1.6-crop lenses will remain strong enough for you to get a reasonable price for it."

 

If you get a FF, the 28/2.8 is a very good wide angle (lack of good, inexpensive wides is probably the largest complaint about 1.6x crop) and the 50/1.8 is _cheap_. The only problem is the Sigma 30/1.4, but if you go FF, then you just sell the Sigma with the 1.6 crop camera. Someone's going to get a real nice bargain, but so what, as long as you've gotten good use out of it, then it was worth it.

[bellavance]

Followup on this subject is here:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00DfTv

 

Pierre

[mike_earussi1]

Just to add another variable to the controversy, the Canon 28 f2.8 is an excellent design but being an amateur lens the build quality can vary widely. I had an especially good one that was almost as good as my friends Leica 28 but have encountered others who hated the lens because it was so bad. It can vary that much. Test a different Cannon 28 and you'll probably get different results.