Contax 18mm f/4 Distagon and A7r

[addicted2light]

This one is a lens for which there aren't many samples or blog posts about, so let's try to make up for that.

 

It is very light and well balanced on the A7r: I even managed to shot with it at 1/4s without IBIS.

 

Colors

It has the usual Zeiss colors, possibly even more so than my other Contax glass. There is a tiny bit of CA, but Lightroom gets usually rid of it just using the automatic settings.

 

Vignetting

Like most extreme wide angles without a connection with the camera (meaning: lenses for which the processor in the camera compensate this automatically even for raw files) it does have quite a bit of vignetting (this was a yellow-ish ceiling; in actual pictures the effect is basically unnoticeable from f/8). But just shooting a blank, out of focus A4 sheet of paper I created a DNG Flat Field correction file for each aperture. As you can see this eliminates the problem entirely. Besides, in real subjects it is hardly noticeable, and quite often improves them IMO.

 

First picture straight out of camera, second picture after correction with FlatField Lightroom plugin. The few remaining "shadows" are actually imperfections in the ceiling itself.

 

f/4

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f/5.6

 

f/8

 

f/11

 

Vignetting in real life

To perfectly clear the vignetting you'll need to stop down to f/11, even though already from f/8 is pretty much gone (all images uncorrected).

 

f/4

 

f/5.6

 

f/8

 

f/11

 

Sharpness

The lens is decently (for a Zeiss, so really good for other manufacturers) sharp at f/4, and at its best already at f/5.6. f/8 is barely distinguishable from f/5.6 in terms of sharpness (less vignetting, though). It looses just a tiny bit of sharpening at f/16 and more so at f/22, but it is still quite usable even if it will require a tad more coarse (i.e. for example a radius of 1 instead of 0.5) sharpening. Great news for landscape photographers!

 

It is super sharp in the center, pretty sharp at the borders, and reasonably sharp in the extreme corners. Not bad at all for an 18mm, IMO. Besides, it even sharpens up considerably at shorter distances (where, btw, you will most of the time have a subject with a lens this short unless you're shooting large landscapes). 

 

I've used it for a "grunge" (or "weird", if you prefer ) male portrait with a LED continuous light and at 1.600 Iso I had to add luminosity noise reduction not because of noise (there wasn't any) but to REDUCE the sharpness...otherwise the facial hairs looked over-sharpened even with the sharpening set at the Lightroom super conservative default level.

 

Smearing and magenta cast

I can't see any smearing or magenta shift at the borders, even on the snow.

 

Flare

It appears to handle flair from exceptionally well to exceptionally badly (see next post); thankfully most times all it takes is a minute change in framing to go from the latter to the former.

 

Distortion

Distortion, as you may already know given it is kinda of a legendary pros of this lens, is basically invisible.

 

 

For now I'm quite satisfied with my purchase; it is not a Contax 21mm in terms of corner sharpness, and that I already knew, but neither it is a 21mm in terms of price, weight and size. For me the tradeoff is well worth the loss of a bit of quality for the possibility to actually have the lens with me, instead that at home in the camera closet.

 

[addicted2light]

A couple of examples of flare, from extremely well to extremely bad:

 

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[addicted2light]

...and finally a few sample images:

 

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[SAR_admin]

Nice!!!

[Marc Contaxtonikon]

thank you this is extremely helpful - is this snow in southern Italy?

[addicted2light]

thank you this is extremely helpful - is this snow in southern Italy?

 

Like I said, we experience a radical change in scenery every 20Km or so. At sea level yesterday you could have been wearing, most likely, a short sleeved t-shirt; on the mountain were I went instead (Monte Scuro, the "Dark Mountain") you needed a few layers more

 

For example, from where I live (the city of Cosenza) I can go in 20 / 30 minutes either to the beach (Paola, 33Km from my front door) or to the place depicted here (1.650m-ish on the sea level, 33Km from my home).

 

In an half-hour time, I can as well go from almost 2.000m peaks (Pollino massif) to sea level (Praia a mare, Maratea, Scalea etc.), or from luscious, tree covered mountains (Sila massif) to arid, almost steppe-like places (the Ionian side).

 

In a sense this is too much: wherever I visit another place I'm always subconsciously amazed of how much more road I have to cover for the place to start to look different!

[nomad]

I second all these observations and I'd like to add: if you just crop the corners a bit you'll end up with a picture nearly indistinguishable from the 21mm. Just a bit less distortion ;-)

No problem with a A7R or R II.

 

 

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[addicted2light]

I second all these observations and I'd like to add: if you just crop the corners a bit you'll end up with a picture nearly indistinguishable from the 21mm. Just a bit less distortion ;-)

No problem with a A7R or R II.

 

 

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I'll add vignetting to those corners anyway, so nothing to see there!

[WeaselX100]

Can anybody add an architecture shot with this lens? I wonder about the (uncorrected) perspective "distortion" of the lens.

 

I own a few 20mm and 21mm lenses and I think it is difficult to use them in cities, resulting frequently in heavy perspective distortion.

[addicted2light]

Can anybody add an architecture shot with this lens? I wonder about the (uncorrected) perspective "distortion" of the lens.

 

I own a few 20mm and 21mm lenses and I think it is difficult to use them in cities, resulting frequently in heavy perspective distortion.

 

 

If you're talking about keystoning (What is Keystoning - Photo.net Large Format Forum), that is difficult to avoid without using a large format camera or a shift lens like the Canon 17mm T&S. The shorter the lens, the easier it is to induce the phenomenon.

 

In terms of actual distortion, instead, the 18mm Contax behaves extremely well, on par with the 21mm Loxia without software corrections and better than the 21mm Contax and Milvus. This means that as long as you keep your camera straight and leveled the distortion will be barely noticeable, especially with a bit of help from LR or PS.

 

You can check Zeiss published MTF charts (that, btw, contrary to almost all other manufacturers are actually measured on a real lens, not calculated as an abstract, theoretical product of the optical scheme employed):

 

18mm Contax

http://www.zeiss.com/content/dam/Photography/new/pdf/en/downloadcenter/contax_yashica/distagon4_18mm_e.pdf

 

21mm Contax

http://www.zeiss.com/content/dam/Photography/new/pdf/en/downloadcenter/contax_yashica/distagon2-8_21mm_e.pdf

 

21mm Milvus

http://www.zeiss.com/content/dam/Photography/new/pdf/en/downloadcenter/datasheets_milvus/milvus2821.pdf

 

21mm Loxia

http://www.zeiss.com/content/dam/Photography/new/pdf/en/downloadcenter/datasheets_loxia/loxia_2821.pdf

[rbelyell]

sorry, i dont mean to be negative, but the set of two tree photos posted to show lack of flare really show a great deal of distortion to me. am i missing something?

[addicted2light]

sorry, i dont mean to be negative, but the set of two tree photos posted to show lack of flare really show a great deal of distortion to me. am i missing something?

 

 

No need to be sorry. But distortion and keystoning (what you're seeing in those two examples) are two entirely different things.

 

Take a look at this article:

 

What is Keystoning - Photo.net Large Format Forum

 

Basically, keystoning is a function of the direction you point the lens at (basically: up), and it happens with any focal length (but we hardly notice with anything that's not wide enough). 

 

Distortion, instead, is a characteristic of the optical scheme that might or might not be present, and it can be of two basic kinds: barrel (it it "bulges" the center) or pincushion (if it "squeezes" the scene in).

 

If you shoot with the camera / lens combo properly leveled you will not see keystoning.

 

As long as you use any wide angle lens to shoot out of level, i.e. upward, you will see keystoning. 

 

Instead, you will see distortion only if it is present in the optical scheme and if it is uncorrected in software (most of modern lenses are automatically corrected in the raw converter software). Besides, in natural scenes it is almost impossible to spot distortion because you don't have anything to compare the scene to. Even fish-eye shots, so pictures shot with a lens purposely designed with boatloads of distortion, often appear "normal" because nature very rarely sports straight lines.

 

If you look at the technical chart listed in my previous post, you'll see that the 18mm has the same amount of distortion as the new 21mm Loxia (in itself quite a feat, given that the 18 is quite a bit wider). Now, the Loxia will be automatically corrected for it in Lighroom, but you can do the same manually dialing in the correct amount for the 18mm.

[rbelyell]

yes, i understand. it seems quite like pincushion to me, especially given the overall look of the scenes i was questioning. it seems to me very typical from this kind of ultrawide, which 'squeezes' areas into the scene by 'bending'. i appreciate your reply though, as i was considering this lens.

[Corlius]

addicted2light, which lens adapter did you use?

And which adapters do other members recommend?

thanks for a great summary.

[Olaf W.]

@Corlius Welcome to our forum, but did you notice that this thread is quite old? Hope you get an answer anyway

[Corlius]

thanks Olaf, actually I didn't    

 

[Olaf W.]

Maybe it‘s better to open a new thread. You should specify the lenses you like to use.