Sigma 24mm f/1.4 Art announced

[D.P.]

http://sigma-rumors.com/2015/02/sigma-announces-24mm-f1-4-dg-hsm-art-lens/

The rumours were true again.

Hopefully gives the canon and Nikon a run for their money.


Personally I'm hoping for new sigma super-teles though.

 

[D.P.]

Official pricing released, $850 which is $50 less than the 35mm Art which is interesting, 24mm f/1.4 is a harder lens to design well than the 35mm and thus nor smelly entails a higher price. My pessimistic side says this lens is perhaps not to the same standard as their 35mm and the Nikon and Canon are still optically superior. I hope I'm wrong and sigma is just being extra aggressive. They do have an older 24mm f/1.8 at a much lower price so perhaps they didn't want to raise prices too far.

 

[D.P.]

Some people noticing the Bokeh is quite rough:
http://g1.img-dpreview.com/B5779F52AB574F8A9EDB16F1BCCD337C.jpg
http://g4.img-dpreview.com/1E8BFD24FC234E78A1B333A3B8E4F3E8.jpg

At 24mm this is somewhat expected IMO but it raises an important point regarding these new Sigma primes (and other lenses from Sigma/Tamron like the 35mm ART and Tamron 24-70mm). There is a tradeoff between wide open sharpness and Bokeh quality related to correcting spherical aberrations. Sigma/Tamorn are focusing on wide open sharpness and reducing OoF rendering quality. This is quite apparent when comparing Sigma 35/50mm ART to Nikon 35/58G lenses.


Personally I don't really see the need to pay the premium for the Nikkors but if you want a lens that renders beautifully at f/1.4 the Sigma art primes may not be the most desirable. For my work I tend to value sharpness higher for landscape, architecture and still life. For Bokeh, the Nikon 24-70mm does extremely well even if resolution figures are outclassed by 3rd party lenses.

 

[D.P.]

"Some" people said the same about the 35mm Art but then were silenced when others pointed out and showed examples of both canon and Nikon having "rough" or "nervous" bokeh in very similar scenes, mostly background foliage on tree branches and whatnot.

It's really not an issue.

I'd like to see what the 24mm aspect does to my Urbex shots. I want a 14mm Art or 14-24mm ideally although the 24mm @ 1.4 will mean I don't have to break out the 17-40 for wide angle interiors and can shoot them tripod free and simply stitch 2 or 3 shots for a wider FOV if needed.

Thinking about it more, the latter makes sense, perhaps the 24mm Art will make its way into my bag too

i don't know about the canon but the Nikon 35f/1.4G produces better bokeh than the sigma, the 55mm does especially well against the 50 ART.

 

[D.P.]

Comparison shots in the same scenes? They both have 9 rounded aperture blades. The bokeh in the same scene between them all would be very similar with only small differences.

The blades aren't the only factor, they merely depict they shape of the bokeh highlights. More important is the actual design of the lens, how well certain aberrations are corrected. Elements like aspherical glass can improve sharpness, reduce Chromatic aberrations cab create a more nervous bokeh with harsh edges.

Complex zoom lens with many different element can lead to a busy/noisy background, even if they have many rounded aperture blades.

For a lens to have better Bokeh ideally you want to slightly under correct the spherical aberrations, this way the edges of the Bokeh highlights are rendered soft. If you over correct the aberrations then the edges end up brighter than the center and you get a very hard Bokeh. The difficulty in zoom lenses is the amount of correction needed will vary through the zoom range. A perfectly corrected lens will have a bokeh highlight as a smooth flat uniform disk, which is OK, but not as smooth as under corrected lenses.
http://jtra.cz/stuff/essays/bokeh/index.html


his is why Nikon made 105 and 135mm f/2.0 DC Defous Control lenses that let the user adjust how much spherical correction to do, thus allowing you to trade sharpness for Bokeh quality. I think Sony has a similar lens. Lenses like the 55mm f/1.4 Nikon are gaining legendary status for the Bokeh quality but are no where near as sharp as the 50mm ART wide open.

Thus a lens even with fewer aperture blades and non rounded blades at that can make nice gorgeous smooth bokeh because the bokeh highlights dim towards the edges. A 12 blade well rounded aperture may cretae perfect circles with harsh transitions to the background.


Recently there has been a move to over correcting lenses, perhaps this increases contrast at the expense of sharpness? Anyway, it makes Bokeh even harsher than normal.

 

[D.P.]

https://cdn.photographylife.com/wp-...Nikon-50mm-vs-Nikon-58mm-Bokeh-Highlights.jpg

Nikon 58mm f/1.4G is leagues ahead of the competition with silky smooth transition from Bokeh ball to background. The sigma 50 ART has a harsher transition to the background since the lens is well corrected. The sigma 50 Art is way sharper than the Nikon and I would buy buy the sigma over the Nikon nanny day for what I shoot but if you like Bokeh then you have to forgo the sharpness and use a less corrected lens.

Funnily the previous sigma 50 had better Bokeh, why, because it was less corrected.

 

[D.P.]

Don't get me wrong, I would rather have the sigma versions for my use and it seems ridiculous to pay more money for a less corrected lens.

 

[D.P.]

Those pixel peep samples don't show any sizeable lead over the Sigma that justifies the huge price difference though^ There's slightly sharper/more immediate green fringing on the Nikon images too. I'm not saying the Nikon (or Canon) versions are bad, they certainly are not, but given the price and performance figures on the table, the Sigmas run laps around the other two.

The crop just makes it easy to compare bokeh characteristics. if you wanted to compare sharpness you would ask poxel peep tight crops.

The bokeh quality of the Nikon's vs the sigma is not my opinion. I don't care that much about bokeh, I'm just reporting what bokeh fanatics see in the images.

If you shoot very shallow DoF photos it is something to think about. For me, I will take the sigmas anyday. The ironic thing is if you want good bokeh you can just buy the older Nikon lenses that don't have aspherical elements. The 85mm f/1.4D is widely regarded as having nicer bokeh than the new G version (although the G version is very good). But is much softer wide open with way less contrast. For portrait photographers many don't care about wide open sharpness and actauly prefer softer dreamier photos that has incredibly smooth bokeh.


When I shoot portraits I prefer longer focal lengths that male the bokeh smoother due to perspective. This gives a much bigger subject separation and more of a 3D look.

 

[D.P.]

The bokeh of the Sigma Art lenses like the 50 1.4 doesn't look as good as the older versions. They do look better everywhere else you look though.

And that is because that optimized for sharpness with a more perfectly corrected lens.

 

[D.P.]

It's better corrected but the bokeh lets it down. You don't always want extreme sharpness and more nervous bokeh, especially with portraits. The Nikon 58G would be my lens of choice even though it is softer it has more pleasing bokeh and would probably be more flattering.

That is what I was pointing out above.