Sigma ART 24/1.4 on Fujifilm GFX 50S

This is the 48th in a series of posts on the Fujifilm GFX-50S. The series starts here.

I still don’t have a lot of wide options for the GFX. The HC 35 works pretty well, but it’s a big, heavy thing. I thought I’d try the Sigma ART 24 mm f/1.4. All images were refocused at each aperture. Cloudy white balance selected in Lightroom, and Exposure to taste with a bit more in the crops; all other Lr settings at default.  

Here’s an aperture series for coverage evaluation:

f/1.41:1 is OK. 4:5 might be.

Better.

4:5 is fine now.

 

 

It doesn’t get to full 4:3 coverage.

Now I’m going to show you some very tight crops; here’s how to use them. The dimensions of the GFX sensor are 8256×6192 pixels. If we make a full-frame print from the GFX on a printer with 360 pixels per inch native driver-level resolution, like the Epson inkjet printers, we’ll end up with a 23×17 inch (58×44 cm) print. The 318×246 pixel crop you’re looking at will end up 0.8333×0.6833 inches (2.12×1.74 cm). Let’s imagine that you or your viewers are critical, and will look at the 22×17 inch print from about 18 inches (conventional wisdom is that the distance would be a little greater than that, or 28 inches (the diagonal), but you did buy a high-resolution camera for a reason, didn’t you?).

The next step is dependent on your monitor pitch, which you may or may not know. Turns out, you don’t have to know it. Just take the 253% crops and view then at 1:1. How high are they? Get out your ruler and measure, or just guess. Let’s say they are 6 inches high. 6 inches is about 7 times 0.8333, so in order to view the crops the way they’d look from 18 inches on the print is to view them from 7 times as far away, or 10.5 feet.

Everything here scales proportionately. If the image on your screen is bigger than 6 inches, increase your viewing distance by the ratio of your image height to 6 inches. If you think your viewers are going to almost get their nose to that print and look at it from six inches, divide that 10.5 feet by 3, and look at the image on the monitor from three and a half feet away.

On a 30 inch 4K display, a 1:1 presentation of these crops will be about 4 inches, so to simulate the effect of viewing the print from 18 inches, you’ll want to back up to about seven feet. A couple of feet for a 6 inch print viewing distance. On a 17 inch laptop 4K display, a 1:1 presentation of these crops will be about 2 inches, so to simulate the effect of viewing the print from 18 inches, you’ll want to back up to about three and a half feet. A foot for a 6 inch print viewing distance. 

In the upper center, at the focus point.

Not bad at all.

Even better.

Very nice.

About the same.

Still good.

Maybe starting to soften a bit.

 

On the far right:

 

Not great.

Better. 

Acceptable.

That’s weird. It worse than f/2.8. Yes, I double checked.

Getting better again.

Pretty good.

In the upper left corner:

Yuk.

Still bad.

Lots of LaCA. Smeared.

More crisply smeared.

Getting there.

OK.

My take on this lens is that it could work for 4:5 and 1:1 landscapes at f/8. For other uses, where the edges are less important, it could be used at wider apertures. On the other hand, a Zeiss 21/2.8 or 18/3.5 on an a7RII would probably work even better.