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05-24-2010, 07:05 PM   #1
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The Politics of Optics

A couple of threads, and a few posts have made me curious about the way people think about lenses.
What makes you decide a lens is worth keeping?
What makes you decide that a lens is junk?

For example, if a lens has good bokeh, but can be forced to show CA/PF, will you keep it for the bokeh or get rid of it for the fringing?

Another example: Is it unadulterated sharpness above all else or can a little softness be forgiven if the lens has other attributes that you like?

I'll jump back in with my philosophy at some point, but I am interested in how other people view a lenses worthiness or lack of same.

05-24-2010, 08:00 PM   #2
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Interesting question. I base my judgement on lenses by it's overall image quality and utility. One of the reasons I sold my fa ltds and my fa lenses was to move to fast, sharp glass that makes sense to carry with me. While I would love to use exclusively Pentax glass (and the glass, after all, is why I stick with the Pentax system) there are focal lengths at certain apertures that it just doesn't cover equitably (namely, where is the DA*70-200 2.8 already?) Though I regret selling my fa77. Even though it's a duplicate focal length, I miss it. A lot
05-24-2010, 08:01 PM   #3
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QuoteOriginally posted by Wheatfield Quote
What makes you decide a lens is worth keeping? Its price/performance, if its the right focal length for me personally, etc.
What makes you decide that a lens is junk? Performance, i.e. sharpness and bokeh. Its physical condition also.

For example, if a lens has good bokeh, but can be forced to show CA/PF, will you keep it for the bokeh or get rid of it for the fringing? Keep it.

Another example: Is it unadulterated sharpness above all else or can a little softness be forgiven if the lens has other attributes that you like?
Its not all about sharpness. The sharpest lens in the world is not one I would like to use for portraits Also non-dizzying bokeh is more important than straight up sharpness. Besides USM helps a lot now-a-days.

I'll jump back in with my philosophy at some point, but I am interested in how other people view a lenses worthiness or lack of same.
Basically I look at a lens and decide whether its worth its price. I.e. my M 85mm. I bought that lens without really thinking, I just jumped on the first one I saw in the marketplace. Price was in the mid $200's. I refused and still do, to spend that much on an old MF film lens unless its something a la A* 200mm macro. I was very weary but it has grown to be my favorite lens I own Was it worth that much? YES. I was close to sending it back when I first got it though :ugh: Its focal length is my favorite on APSC thus far. Its sharpness @ F/2 is very sharp. This lens is a beauty at portraits because despite its sharpness, DOF is so small usually only the eyes are in focus making it ok. From F/2.8 on its crazy sharp

Another different example is my DA 55-300mm. I bought it for a great price (to bad Gus isn't here anymore. He could re-call how upset he was that I PMed the guy just before he did, because of its great price ) here on the market place despite me not looking for this lens. I simply saw it and jumped on it so to speak I HATE zoom's and this is no different with this lens. Its performance is pretty good but not any where near prime territory. Its build is crap compared to my old M lenses, and its focus ring and zoom ring are both terrible to turn feal wise. Despite this I keep it. Why? Well the great price is one factor, and the other is the fact that I now own nothing longer than 135mm. If I ever need longer thats the only lens I can grab. How often have I grabbed the lens and used it in the field? Maybe twice Its there when i need it though, and until I can afford something better it will continue to stay in the bag ready....

edit: I'd like to add the DA 55-300mm is the best lens in that range of any brand I've used to date....
05-24-2010, 08:11 PM   #4
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It has to be a combination of everything, IQ, CA, vignetting, distortion, etc.. (price does not matter because no matter the $ if the IQ is garbage the lens is garbage, period) and does one aspect out weigh the other? For example my Tamron 70-300 is a purple monster but the images are very sharp so I am going to keep it (unless I can get a DA/L 55-300).

On the other hand I had a F 28-80 which I found the IQ to be terrible and I sold it asap even though I only paid $40 for it.

Actually now that I think about it, it's all about great/sharp IQ. If a lens can produce a very good image than it is worth keeping. If the image is soft, not sharp, has focal issues then it is definitely not worth keeping. Even a zoom lens that has zero CA but produces a really soft unsharp image then why keep it?

05-24-2010, 08:16 PM   #5
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I can see that this is all going to vary greatly depending on our actual experiences. I didn't even think about distortion because I've never liked shooting wideangle therefore I've never had a lens with noticeable distortion. Same with CA/PF... I've never had a lens that showed these traits often or in a mannor that wasn't easily contained/removed.
05-24-2010, 08:23 PM   #6
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QuoteOriginally posted by Wheatfield Quote
A couple of threads, and a few posts have made me curious about the way people think about lenses.

What makes you decide a lens is worth keeping?
Well First, I read and pour over 1000s of charts, reviews, and pictures of brick walls and newspapers.

QuoteQuote:

What makes you decide that a lens is junk?
See above.

QuoteQuote:


For example, if a lens has good bokeh, but can be forced to show CA/PF, will you keep it for the bokeh or get rid of it for the fringing?
In all seriousness, If a lens gives me results that please Me, I keep it. I can make just about Any lens PF, so it really isn't even a factor. If I enjoy Using a lens, I keep it (which is why I've sold every FA I've ever owned). The rest go. It is really that simple for me.

I'll never purchase most of them again for what I originally paid so unless I'm about to get out the bottle of ketchup to eat the lenses (because I've spent myself into the poor house), they stay here. The lenses I would typically sell are lenses that I have Better copies already in my collection or dupes that I've somehow aquired.

It really IS, that simple.

05-24-2010, 08:41 PM   #7
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Imho, the answer is not so cut and dry as "keeper" or "junk"

I tend to spend time using a new (typically new to me) lens at different times over a long period in different situations until I can determine character, best use, etc., before I decide if I already have a better lens with similar qualities. I have learned something from each and every lens. I use a complete set of M42 S-M-C Takumars from 17mm to 500mm that has served as a basis to compare; photos posted by others also serve as a guide for purchases. Often I will buy nearly any lens that cost me less than $20US delivered; there have been some lemons, though I wouldn't go so far as to say "junk" maybe because I've never (yet?) gotten a truly bad lens. Some have been really surprising stunners.

05-24-2010, 10:59 PM   #8
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What makes you decide a lens is worth keeping?

If I wanted it enough to buy it, then it's worth keeping.


What makes you decide that a lens is junk?

Junk lenses fall apart. Hopefully none of mine fall apart.

There are many lenses I will not buy because I don't have a use for them, that doesn't mean they are junk. Case in point, I'll never buy the 12~24, even if the price drops in half. I don't need it and I don't want it. I chose the Sigma 10~20 and the DA15 instead. They are better lenses for me, but that doesn't mean the 12~24 is junk.
05-24-2010, 11:17 PM   #9
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I tend to value sharpness and speed. I can forgive a little CA and wierd bokeh if the lens is fast and sharp. If it has weather sealing that's a plus too.
05-24-2010, 11:51 PM   #10
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"What makes you decide a lens is worth keeping"

- To me, sharpness and control of abberations (I include nasty bokeh in that) trumps all. For modern lenses, softness cannot be forgiven unless I am getting something in return; like f/1.4 or a cheaper cost. In the digital age, everything else is like arguing how many angels fit on the head of a pin. Processing in-camera and post have more effect on how the image is going to look.


"What makes you decide that a lens is junk?"

- If it has SDM.

Last edited by PentaxPoke; 05-24-2010 at 11:59 PM.
05-25-2010, 01:39 AM   #11
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QuoteOriginally posted by Wheatfield Quote
What makes you decide a lens is worth keeping?
I buy/keep a lens for a particular purpose, e.g., portraiture.

It should excels at least one thing. I look for versatility (which is why I like lenses with close focusing ability), sharpness (you can always blur in PP but not create resolution), and good bokeh (combined with subject "pop"; would love to own a 85/1.4 or the 77/1.8).


QuoteOriginally posted by Wheatfield Quote
What makes you decide that a lens is junk?
If IQ below f/8 isn't up to scratch. It may be a sign of lens appreciation immaturity but I don't like lenses with weird rendering caused by technical incompetence. If I want to an artsy look, I'll create it in PP.

In the same vein, I don't think a lens can be "too sharp". For a portrait, I like lashes and eyes to be sharp and will soften other areas in PP. There are only a few select images than can get away with nothing being critically sharp, AFAIC, so I'm not a fan of lenses that do the portrait softening for you.
05-25-2010, 02:12 AM   #12
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For me a lens is only "junk" if it is not useable for the purpose.

I only have one of those lenses, an XR rikenon M42 135 mm lens that while it produces good and sharp images, suffers badly from sensor reflection.
05-25-2010, 08:34 AM   #13
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I too would say it's all about usability for me. Either they help me get shots I wouldn't get otherwise or they don't. Helping me get shots I wouldn't get otherwise might mean larger maximum aperture than anything else near that focal length, better able to fit in my bag, or IQ noticeably better in some way.
05-25-2010, 08:39 AM   #14
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Just to be safe, I keep 'em all.
05-25-2010, 09:39 AM   #15
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I often get sidetracked by either price/value, or niggling performance differences. But in the rare moment of actual photography, I will sometimes take a great photo with a lens. That photo trumps all.

At this point, my skill makes many of the technical properties just theoretical. For example, the SMC Pentax 300mm f4 has CA, easy to demonstrate in a test shot. But if I cull an image from that lens, it's because of focus, motion blur, exposure, etc.

I have one lens with few redeeming optical qualities, except my parents gave it to me. It's also big and heavy, and from the first day, operates strangely. It's not worth much. Keeping it anyway.
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