Lens question re: sharpness

Started Jul 2, 2012 | Discussions
joelroffman
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Lens question re: sharpness
Jul 2, 2012

As a general rule, are prime lenses sharper than zoom lenses?

Deleted1929
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Alas there is no general rule
In reply to joelroffman, Jul 2, 2012

The way sharpness varies over the frame and at different apertures and focal lengths means that there's no way to make a general rule for this.

If you're asking will a prime lens get me more sharpness then in general the answer is no, IMO.

Sharpness is generally a result of understanding the importance of shutter speed and/or tripods and the performance characteristics of a particular lens at any give focal length and aperture. This combined with good understanding of depth of field and how the AF system works ( and when it doesn't work well ) are all important.

Modern kit zooms are generally very sharp and if you're not getting a sharp shot from them it's typically not the lens that's the problem.

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StephenG

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hotdog321
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Re: Lens question re: sharpness
In reply to joelroffman, Jul 2, 2012

Generally, that is correct. Zooms are an amazing compromise of complex moving lens elements. This creates some focal lengths that are sharper than other focal lengths on the same lens. Fixed lenses are optimized for a single focal length and have fewer compromises.

That said, today's quality zooms are absolutely amazing and often come near to the sharpness of a fixed focal length while being far more flexible. For instance, juggling a bag full of fixed lenses can be a real hassle and cause you to miss shots or damage lenses when in a hurry.

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John Deerfield
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Re: Lens question re: sharpness
In reply to hotdog321, Jul 2, 2012

I would have to say that as a general rule rule, yes, primes are sharper than zoom lenses. The most obvious reason being simpler construction (fewer groups/elements) and working at only one focal length. There is also the principle that any lens is going to be sharper when stopped down. You have to stop down a f/1.8 lens 1 1/3 stops to get to f/2.8. By simply physics alone, the prime will be sharper. And lets face it, not many people are running out and dropping almost $2000 on a Nikon 24-70 f/2.8 lens, which is a truly great lens and sharp wide open @ f/2.8. I have yet to have any type of consumer zoom or even third party f/2.8 lens be as sharp at their widest apertures as a prime lens will be at that same aperture . Again, one reason being that the prime is stopped down at that point. And some lenses, such as "superzooms" will never hold a candle to a prime lens. That said, I shoot with a 18-200mm lens all the time. It is a matter of understanding that every lens is a compromise to achieve a result. From engineering to use in the field. I use the "superzoom" so that I don't have to swap lenses all the time. The consequence is that image quality suffers.

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Ysarex
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Re: Lens question re: sharpness
In reply to hotdog321, Jul 2, 2012

The tool that is optimized to do the simple single task will do that task better than the multi-purpose tool.

Ask a lens designer to make an incredibly sharp, color corrected, full contrast lens as close to perfect as possible to photograph the landscape at infinity at a fixed aperture of the lens designer's choice with no concern for cost:

superb performance.

Ask that the lens be able to focus over a range from 2 feet to infinity as well.

Ask that it have a variable aperture and be able to function well over that aperture range.

Ask that the maximum aperture be very fast like 1.4.

...........................................................

You've already asked for enough to compromise performance. Consider this: In the days when the industry still had a shred of integrity Leitz use to sell two lenses for the Leica M3 -- a 50mm f/2 Summicron and a 50mm f/1.4 Summilux. The Summilux sold for $$$ more than the Summicron yet in their advertising literature Leitz actually admitted in print that the Summicron was the optically superior lens. They went on to explain that the compromises necessary to increase the max aperture to 1.4 on the Summilux required some loss of performance and unfortunately raised the manufacturing costs. They made the lens for those that needed it but actually advised in their sales literature that customers buy the Summicron unless they really had to have that 1.4.

.........................................................

Ask that the lens be able to zoom over a range of focal lengths.

Ask that it "super" zoom from wide angle to telephoto -- 20X!

Ask that the lens have macro or near macro focusing capability.

Ask that the lens be small and light.

Ask that the lens not cost $10,000.00

Ask that the lens in fact cost less than $1000.00:

Are you bleep bleepin' serious?!!! And you want it to take pictures?!!!

...........................................................

I use some zoom lenses and I'm very happy with them overall factoring cost/performance. I have Canon L series zooms and they're pretty good, but I have also used that 50mm f/2 Summicron and the difference is real. I've used a 100mm f/3.5 Planar and the difference is real. I've used a 28mm f/2.8 Biogon and the difference is real, etc.

Joe

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Barrie Davis
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Re: Lens question re: sharpness
In reply to joelroffman, Jul 2, 2012

joelroffman wrote:

As a general rule, are prime lenses sharper than zoom lenses?

It used to be true, but it isn't now. Some modern zooms are startlingly good performers ...

... especially those that most "emulate" a fixed focal length prime lens.... (have short zoom ranges.)

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Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

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Wally626
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Re: Lens question re: sharpness
In reply to Barrie Davis, Jul 2, 2012

It is certainly true that many modern zooms are pretty good, especially the more expensive limited zoom range ones, but it is very difficult to be sharper than a good prime lens. There are some cheap primes that are not all that sharp, so prime does not always mean sharper, but the more expensive ones are usually very good. My Zeiss Jena Sonnar 135mm f/4, is by far my sharpest lens, it is very easy to see the difference at 100% zoom. In an 8 x 10 print not so much, so it most cases the sharpness is wasted, but it is there if needed.

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nelsonal
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Re: Lens question re: sharpness
In reply to joelroffman, Jul 2, 2012

Yes, though with reservations. First to paraphrase Tolstoy, sharp photos are all alike; every unsharp photo is unsharp in it's own way. His masterful turn of phrase means that to result in a sharp photo, a combination of conditions must all combine to result in a sharp photo, if any one of them is lacking, the photo won't be very sharp.

So, if technique is good, then generally primes allow better sharpness than similar quality zooms. Very good primes are generally sharper than very good zooms (compare say the Samyang 35mm to just about anything at matching apertures). Good primes are generally sharper than good zooms but may not be as sharp as very good zooms, etc. Single primes usually cost less than zooms of similar quality, but to cover most of the focal legths in a zoom with equal quality primes is usually considerably more expensive. The whole debate is pretty moot, though, unless everything else that can contribute to sharpness in a photo does.

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Alleg1
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Re: Lens question re: sharpness
In reply to Wally626, Jul 2, 2012

Wally626 wrote:

It is certainly true that many modern zooms are pretty good, especially the more expensive limited zoom range ones, but it is very difficult to be sharper than a good prime lens. There are some cheap primes that are not all that sharp, so prime does not always mean sharper, but the more expensive ones are usually very good. My Zeiss Jena Sonnar 135mm f/4, is by far my sharpest lens, it is very easy to see the difference at 100% zoom. In an 8 x 10 print not so much, so it most cases the sharpness is wasted, but it is there if needed.

Well said..In my opinion you've put forward a concise and sensible summary. The notion that primes are always superior to zooms is rather outdated.

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