Sigma 85 f/1.4 Art

[Sean Setters]

I think the price difference is small enough that many people will choose to go for the Canon w/ IS, which is bad news for Sigma. Hopefully, it doesn't discourage them from making more awesome and relatively affordable lenses.

Indeed, 4-stop IS + [an expected] more accurate AF system will more than justify the price difference for many. I'm generally a fan of Sigma's Art-series lenses (I still have 2 in my personal kit). But if I were shopping for an 85mm prime today, I'd pick up the EF 85mm f/1.4L IS USM in a heartbeat.

[Kayaker72]

Ha.....so if I was in the market for a 85 mm prime, I would definitely be interested in the EF 85 f/1.4 IS. And I am not appalled by the price point. But my original estimate of it being over $2k was contingent on optical quality being the same or better as the Sigma 85A and the recent Canon EF 35 II. I am not sure it is. At least looking at the MTF (which is theoretical), it is not.

Canon EF 85 f/1.4 IS




Canon EF 85 f/1.2 II




Canon EF 85 f/1.8




EF 70-200 f/2.8 II

I am not going to include Sigma's MTF as different manufacturers = different MTF, but it is somewhat similar if they are somehow comparable.

But, comparing Canon MTF to Canon MTF this is a good, sharp lens, but I will be pleasantly surprised if it hits the optical level of the EF 35 f/1.4 II or the Sigma 85A, especially wide open. But, still, with 4 stops IS, if I was to pick one, I might go with it.

EDIT...

BTW, I pulled the MTF chart from:

http://cweb.canon.jp/ef/lineup/stand...f14l/spec.html

[Joel Eade]

Are all those MTF charts at the same f-stop?

[Kayaker72]

Are all those MTF charts at the same f-stop?

Hi Joel,

The blue lines are f/8 and the black lines are wide open. So, of course, wide open will vary between the lenses. The thick lines are 10 line pairs/mm (indicator of contrast) and the thin lines are 30 lp/mm (indicator of resolution). Further up the chart, the better, the closer the solid to dashed line, typically the more uniform the bokeh.

A quick write up on it from Canon and luminous landscape:

http://www.learn.usa.canon.com/resou...F_charts.shtml

https://luminous-landscape.com/mtf/

I would say that the new EF 85 f/1.4 IS is a bit better than the EF 85 f/1.8. So, the IQ you have at f/1.8 with older lens, you'll now have a bit better at f/1.4 with 4 stops IS with the new lens. And the 85 f/1.8 is plenty sharp. So I expect the new lens to be great. But, it is just a little bit behind the EF 35 f/1.4 II:
http://www.the-digital-picture.com/R...mp=0&APIComp=0

the Sigma 85A:
http://www.the-digital-picture.com/R...mp=0&APIComp=0

or the Zeiss Otus:

http://www.the-digital-picture.com/R...mp=0&APIComp=0

At least that is my perception based on the MTFs.

As I thought about this, as a portrait lens, that is likely fine. Good bokeh/contrast is as important if not more so than straight up resolution. And looking at the MTF, 10 lp/mm is almost at 90% on the 85IS, so I expect good contrast. Resolution is down around 60% which is meh. The dashed and solid lines are reasonably close, so I expect fairly uniform bokeh. This should be a good portrait lens, but the MTFs are not indicating that it is a world beater in terms of resolution.

[Dave Throgmartin]

If you need a 85mm lens the Sigma Art looks awesome.

Dave

[Kayaker72]

BTW...I was playing with the Sigma 85A compared to the new lens yesterday. One thing that impressed me was how well (not perfect but ballpark) the Sigma MTF matched with what lensrentals observed:

85A Geometrical MTF



Sigma MTFs explained (v different from Canon)
https://www.sigmaphoto.com/lenses/le...tf-chart-guide


LensRentals measured MTF
Olaf Optical Testing, 2017


So, comparing the two red lines (both 10 lp/mm wide open) and the two green lines (both 30 lp/mm wide open), some serious similarities. If anything, the lens tested better than the MTF would have indicated.

I checked out the 50A, and the same generally appeared to be true. Nice to see some MTFs validated.