Saturday, November 30, 2024

Comparing compact 85mm lenses

After obtaining a new lens I enjoy making a few quick comparisons with what I already own, so that I can determine the strengths and weaknesses of each optic. These test are not meant to be scientific, so please take with a grain of salt. Sample variation may have a large bearing on the results. 

In this article I will compare three compact 85mm (or thereabouts) lenses available (from Olympus, Carl Zeiss, and Pentax) with the native Panasonic Lumix counterpart. I find this focal length particularly useful for gig photography, since in the small places I frequent, anything longer would put people between myself and the subject on stage. Anything shorter won't have the reach needed to isolate a performer.

The four lenses

Olympus OM-SYSTEM Zuiko AUTO-T 85mm 1:2 (1979)

  • 47mm long
  • 260g
  • 85cm close focus 
  • 49mm filter
  • 8 blade iris
  • 5 element in 4 group

This is the fourth and last variant of this lens (serial number above 204,000) with the newer “NMC” lens coating. I have recently discussed this lens in a series of three articles.

Carl Zeiss Sonnar T* 2.8/85 (1975)

  • 47mm long
  • 230g
  • 100cm close focus 
  • 55mm filter
  • 6 blade iris
  • 5 element in 4 group

I have written a full review of this great lens.

smc Pentax-FA 1:1.8 77mm Limited (1999)

  • 48mm long
  • 270g
  • 70cm close focus 
  • 49mm filter
  • 9 blade iris
  • 7 elements in 6 groups

This an auto-focus lens that uses a screw mechanism. The fit and finish is excellent, complete with a pull-out hood and felt-lined cap. The optics are based on the previously released Pentax-A* 1:1.4 85mm. But Jun Hirakawa tweaked the optical formula for a unique balance of aberration correction (less) with dimensional rendering (more). Well, almost unique, as he did the same with the FA 43mm Limited.

I absolutely loved this lens when shooting a Pentax system. The only limitation is the purple fringing against high-contrast backgrounds.

Panasonic Lumix S 1:1.8 / 85mm

  • 82mm long
  • 355g
  • 80cm close focus 
  • 67mm filter
  • 9 blade iris
  • 9 elements in 8 groups

This excellent lens is made with two ED (Extra-low Dispersion) elements that have eliminated chromatic aberration. It has negligible breathing, low vignette, great flare control, almost zero distortion (0.07%) and amazing sharpness. Really there's no technical reason to prefer a vintage lens to what current technology can provide. But what I like about is their handling and compact size. Hence this comparison.

The crystal test

All tests were performed using my Lumix S5 body on a tripod with IBIS turned off and a delayed shutter to ensure stability. Developing was in Affinity Photo with almost all my usual settings turned off. A slight bit of clarity was maintained since this only reveals what is actually in the image, as opposed to artificially sharpening. A properly developed image will look nicer than these samples.

I took a 1000 pixel square from the centre of each image and mosaiced these for comparison at several apertures.

The first subject was fruit in a crystal display setting. I was hoping the backlighting would enhance any chromatic aberrations or flaring. It's winter in Ireland... there is no good light! Distance was about 1.4m. 

You should click on these images to view a full-sized versions. Make your own observations.

The Olympus is already capable from wide open. Indeed, this example shows no improvement stopped down to F2.8, but a dramatic increase in detail and precision occurs at F4. This strange behaviour could be an artifact of this particular test. Or perhaps my focusing was off. By F8 the image looks fantastic, as we'd hope for any decent lens.

The Sonnar is completely usable from wide. Not sure what else I can say about this wonderful lens that I haven't already covered in my review.

I didn't shoot the Pentax Limited wide open but rather stopped down slightly to F2. Even at F2.8 it doesn't quite have the clarity of the Sonnar. There's no sign of purple fringing in the glass, which was a welcome surprise. The screw motor means that the manual focus feeling is not as nice as the Olympus and Zeiss. It's not even as smooth as the Lumix, since Panasonic implement a customisable focus-by-wire system that is quite amazing (for an auto-focus lens).

The Lumix leaves nothing behind in terms of pure image quality, as you'd expect for a contemporary design. The entire Lumix line is superb. Even the 20-60mm kit lens, which made me rethink my expectations of a cheap zoom.

It's clear from the images that these lenses have a range of magnifications, despite their focal length designations. The Pentax displays the widest field of view, as we might expect from a unit labelled 77mm. But that number was chosen for its associations with good luck in Japan and is no doubt an approximation. The Lumix has a very similar FOV, followed by the Olympus and then the Zeiss. Consulting the Zeiss technical notes, we see that the focal length is specified at 87.6 mm. Rounding off a bit, here's my guess as to how these lenses relate:

  • Pentax: 78mm
  • Lumix: 80mm
  • Olympus: 85mm
  • Zeiss: 88mm

These small differences may or may not matter, depending on the rest of your kit. 

Though by no means a stress test of bokeh, since the background is so far from the focal plane. All of these images have a nice smooth background with no disturbing qualities. I'd say that the Olympus renders more smoothly than the Zeiss, likely due to the increased colour saturation and contrast that the Sonnar is known for. One characteristic plays off the other. 

The colour test

My second subject is a knitted throw made of coloured wool, chosen for the diverse hues. I omitted the Lumix lens and F8 for this test. The subject was at a slight angle to the camera, so that even if I missed focus, part of the material would indeed be sharp.

Here the Olympus operates as expected, the previous test notwithstanding. Wide open the image lacks clarity but is very tight and detailed already at F2.8. It doesn't gain in quality as you stop down from here, which in practice means that you can choose your aperture strictly based on the desired depth of field.

The Zeiss is sharper than the Olympus at F2.8 and has deep, saturated hues that are difficult to find elsewhere. I know this from practice. Sometimes I need to back off on the contrast and saturation during development because the Sonnar is altogether too vivid!

The Pentax Limited comes into its own at F4, which is something I know from experience. For portraiture, at the usual expected distances from the subject, F4 is also perfect for rendering enough of a face in focus. Indeed, when close to my subject this might not be sufficient. As evidence I present Schweppes at F4 (taken with the Olympus 85mm). Focus is on the nose, but the eyes are not yet quite sharp.

Conclusions

Despite taking these attributes into account in this comparison, it must be said that neither colour nor contrast are that important. Back in the film era one might choose stock specifically for its colour rendering and how this interacts with a specific lens. Now, both characteristics can be tweaked instantly in digital development.

I bought the Olympus 85mm since I had never shot with any OM Systems optics and kept reading about how highly-regarded they are. The prices are rather astronomical for some of the lenses, though the 85mm is not out of line for a vintage lens. And it is the most compact 85mm that does F2.

However, following my tests (and other shooting) I won't be using the Olympus at F2. That restriction puts it up against the Zeiss Sonnar, which cannot be beat on image quality and is fractionally smaller. It's also much nicer to use. The Olympus aperture ring is too loose and I don't like the placement at the front of the lens. It's too easily knocked in normal use.

Ergonomics is important. In fact, it's why I am using vintage lenses in the first place. The smooth focus rings and visible apertures are two reasons I prefer these over contemporary products.

The Pentax unfortunately can't compare since its focus ring is optimised for auto-focus. However it has the advantage of close focus distance, only 70cm. The Sonnar is the worst in this respect at 1 m. And that is its only limitation.

Finally, I should remark on the slightly veiled look of the Olympus. This might be the result of a slight hazing of the elements. Then again, this might be considered a desirable aesthetic, especially for portraits. There is such a thing as "too sharp" when rendering skin.

Reality check: Any and all lenses will take great pictures once you know the strengths and weaknesses. But the small details matter when you wish to get the most from your tools. I hope this article has helped in that regard. 

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