24mm camera lens shootout, on the Sony a7R: second round

This second round of 24mm legacy camera lens testing will continue to focus on picture quality at the sides of the image, by comparing wide landscape test photos. As we saw in the first round of 24mm lens testing, there can be a huge disparity in picture quality at the sides, with the Sony a7R, to the degree that it overwhelms just about any other aspect of image quality. This issue with picture quality at the sides of the a7R images is far less of a problem at focal lengths of 35mm and longer.

A second copy of the Canon Fdn 24mm f/2.8 lens makes an appearance in this round, mounted on a different adapter, this time it’s a black no-name Ebay adapter. The lens has a light haze over about a third of the front glass, and a sticky aperture ring. The other two lenses being tested are the Kiron 24mm f/2.0(Pentax k-mount), and the Olympus 24mm f/2.8. All shots were taken with the Sony a7R, on a monopod, at f/8, iso200-250. Both of those lenses are nearly perfect in appearance; no haze, no fungus, and clean snappy aperture blades.

Ease of focus at long distances: The Canon FDn 24mm lens has a significantly longer focus throw than both the Kiron 24mm and the Olympus 24mm, and it’s noticeably easier to turn. Contrast is important for focusing wide lenses at extreme distances like this, and the Olympus 24mm may have a slight edge there. The Kiron 24mm optic is legendary, when you hold it in your hand, and marvel at how big the front and rear glass is, it’s hard to be subjective. The diminutive Olympus 24mm lens is perhaps the best match for the small a7R, depending on what your preferences are. In the end, none of them had quite the same pop that the 24mm smc Pentax did in the first round, so it’s two points for each camera lens.

Lens contrast: The test target being photographed in this round wasn’t as helpful for looking at contrast. The “5610” number from the first round was at a closer distance, and the thin lines of that number, against the light background, made a decision about lens contrast seem easier. In this case, the focus point was on the highway sign, and it’s numbers are unreadable, against a green background. We are left with looking at bushes on the hillside to the left of the sign, and the trees far away in the distance. The Olympus 24mm seems to handle vertical telephone and street light poles with slightly better clarity, in the center of the image, so 2 points for it. The Canon FDn 24mm may edge the Kiron 24mm out slightly for contrast, but since there aren’t any half points available, 1 point for each.

Sides of the images: This is where the differences are much more noticeable, which is why it’s so important. The second copy of the Canon FDn 24mm, with all of it’s issues, still clearly wins by a long shot on the right hand side. The Kiron 24mm goes down hard on the left hand side, bringing up the question of whether or not it’s decentered in that area. The Olympus 24mm could have issues on the right hand side, but it’s fairly solid on the left hand side. If you look at the rocks under the bridge, on the left side side, the Canon FDn edges the Olympus lens out slightly, so it’s the winner. Canon FDn 3 points, Olympus 24mm 1 point, Kiron 24mm(disqualified) zero points, it never won on any side.

Center of the images: Possibly the Olympus 24mm, but you’d have to analyze the RAW images to be sure. What you are looking at are cropped then recompressed camera original JPEGs, so it’s difficult to be sure. The Kiron 24mm might be the weakest of the three here, but is it enough to hand out points on?

Summary: The Kiron 24mm(3 points) is out, but can it’s sides be salvaged at f11? What about slight front focusing? Those are questions for the consolation rounds. The Olympus 24mm(5 points) moves forward, even with it’s possible weaknesses on the right side. Out of the five lens designs tested so far, the Canon FDn 24mm(6 points) is showing signs of being the most compatible with the Sony a7R.

Here is the test image for this round, it’s nearly 12mb in size, **be sure and view it at 100% size**:

http://www.codectest.com/images/24mmCanonFDnOlympusKiron.jpg

Dan Euritt

24mm camera lens shootout, on the Sony a7R: first round

24mm camera lens shootout on the Sony a7R: third round, Konica 24mm

24mm SLR prime lens test, fourth round, shot on the Sony a7R

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