So, what to look for in a lens?

[erniethemilk]

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So, I’m interested in knowing how you analyse a lens to find out if it’s a keeper or not. 

I’ve always had lenses on the basis of if it produces what I like I’m happy with it, however it doesn’t take into account such things as CA, corner sharpness etc. 

So how do you figure out the technicalities of a lens. 

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[Michael Hiles]

Is you goal to take pictures? If YES, then you had it right. Do you like the pictures it produces? Is the lens easy to use? If you are a photographer, then the technical stuff is mostly irrelevant.

If you are mainly interested in geometrical optics or mechanical engineering, then buy the technically best you can afford and pursue the technical information that is available. But IMO this is not photography.

Edited January 7, 2022 by Michael Hiles

[jdlaing]

And test it endlessly. Compare it to other lenses endlessly.😃

[evikne]

Important: 

• size
• speed
• design
• handling / tactile feel
• color rendering
• contrast rendering
• OOF rendering
• reasonably sharp
• a price I can afford
• must be a Leica lens!

Less important:

• weight
• flare resistance
• vignetting
• CA
• distortion
• corner sharpness

Not important:

• high resolution
• high acuity
• micro contrast (whatever that is)
• "latest and greatest"

 

Short MFD is pretty important, but one of my favorite lenses still doesn't meet this requirement. 😉

Edited January 7, 2022 by evikne

[spydrxx]

I look for ease of use...does everything operate smoothly and is the glass relatively clean and clear, as most of my lenses are vintage. When I get around to actually using a lens to take photographs, I look for how it renders subjects, centrally and toward the edges of the field. Outside of those criteria, I rarely am concerned with the boatload of technical characteristics. I've had too many lenses over the years which got raving technical reviews, but as far as I was concerned, produced ho-hum results with my subjects.  I take personal credit for often uninspiring photographs, but I want those results to be a function of the photographer, not the lens. I've found most lenses do a fine job, some better than others...but determining if a lens is a keeper, seems to me to be a function of personal preference for rendering rather than technical characteristics.

[RexGig0]

I may desire a lens for the way it corrects everything, in a near-perfect way.. I may desire a different lens because of its lack of technical perfection, which results in its character, or its signature. My Elmarit-M 28mm f/2.8, Version 3, produces some very cinematic images, that are technically very imperfect. Loads of cinematic flare. The newest version of this lens, the Elmarit-M 28mm f/2.8 ASPH, with a Leica manufacturing code of 11677, also written as 11 677, is very much a well-corrected lens. If I want to shoot “serious” landscapes, with a 28mm M-mount lens, I would probably use the 11677. I do not yet own an 11677, but do have a Zeiss Distagon 1,4/35mm ZM, which makes very technically corrected images. Sooner or later, I may well add the 11677, but I might rather prioritize a Leica-M Super Elmar 21mm, which is another well-corrected lens.

Another lens that one uses, to take advantage of its lack of correction, is the Thambar-M 90mm. When I had an opportunity to acquire one, pre-owned, but in perfect condition, I bought it. There is an ongoing discussion, of the Thambar lenses, in this forum. I already owned superbly-well-corrected 90mm and 100mm macro lens, which I used on DSLR camera, so, it made sense to select a Leica-M 90mm lens with a notable lack of optical correction.

I photographed so very many living, breathing assault victims, some number of dead people, crime scenes, and evidence, with Canon DSLRs, and very-well-corrected Canon lenses, with exposures being so perfect, because editing of images was forbidden, due to the requirement that evidence not be altered. The Leica M system was a retirement gift, for myself. So, well, yes, I will have another serving of that uncorrected artistic imperfection, please. 

Some Leica shooters will prefer lenses designed by a particular individual person, such as Walter Mandler, or Peter Karbe. A shooter may share a designer’s vision, to the extent of wanting to only use that designer’s lenses. I have an affection for Mandler lenses, with that above-mentioned Elmarit-M 28mm Version 3 being an example.

Well, I think I have typed enough, for now. I have difficulty composing meaningful closing paragraphs.

Edited January 7, 2022 by RexGig0

[lct]

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As far as IQ is concerned, i check features i find more or less difficult to tweak in PP, mainly acutance, bokeh, flare and color fringing.

[LocalHero1953]

I suppose there are a lot of things I look for in a lens, but then I look at a lot of them in passing, as it were, without consciously thinking about it - the feel in the hand, on the camera, the usability, the looks.

I rarely (never?) evaluate the technical optics of a lens. (a) it is boring and (b) I do enough reading of reviews by others I trust (especially here) to be sure that the lens is likely to have the optical properties I want. I don't normally look at photos by others as an evaluation method - too many variables, and they don't take the same type of photos I do (an exception is @Milan_S's wonderful burlesque-style photos with the new Thambar, which sold it to me, even though I do more straight portraiture than burlesque!)

I do consciously evaluate a lens for its photographic qualities: the qualitative impression I get when I look at photographs taken with it. I try to do the same type of evaluation for any image-critical item: digital camera, lens, film. I take a series of shots each of:

• Vegetation, trees and natural landscape, including sky.
• Buildings and urban landscapes, interiors, and materials like wood, stone, concrete etc.
• People, faces, hair and skin.
• Metallic objects, cars and specular reflections.

I don't try to take exactly the same shot with each camera, lens or film. That is why I take quite a lot of each group of subject matter, so that I can evaluate my own, subjective, aggregated impression of the performance with each group.

If (if!) I have done my preliminary research right, my photography will never be limited by the optical and mechanical properties of the lens.
The purpose of my evaluation is to understand how best it can help me take better photographs.

Edited January 7, 2022 by LocalHero1953

[pippy]

Fundamentally how it renders. Everything else is secondary. If I like how a lens 'draws' then it will get used a lot. Vague, I know, but it's hard to be more precise.

Physically I much prefer small lenses. Light lenses are at an advantage.

That's about it.

Philip.

Edited January 7, 2022 by pippy

[Guest]

1] how the lens renders.

2] don't give a damn if its voigtlander,leica or 7 artisans.

3] dislike perfect sharpness wide open or even close to it .

4] must  be no more than £1,000 approx although my 50mm summicrom V 5 did cost more when i bought it used some time ago.

 

[Ko.Fe.]

It has to provide pleasing images. Film and digital, bw and color. 

It has to be under normal size.

It has to have not a Zeiss Wobble quality build.

It has to be smooth to focus, not too long focus throw and aperture ring has to the half-clicks, easy.  

Edited January 8, 2022 by Ko.Fe.

[Ray Vonn]

13 hours ago, pippy said:

Fundamentally how it renders. Everything else is secondary. If I like how a lens 'draws' then it will get used a lot. Vague, I know, but it's hard to be more precise.

Physically I much prefer small lenses. Light lenses are at an advantage.

That's about it.

Philip.

Following this excellent response, I believe there's nothing more to be said, this thread can now end. That's basically it in a nutshell.

[BradS]

With Leica M mount lenses, my primarily considerations are:  cost,   physical size,  focus shift,  and  flare characteristics.

 

 

[BradS]

I'll add that I take lens reviews with a grain of salt. The vast majority are comically poetic, vacuous or meaningless.