Pages: [1]   Go Down

Author Topic: Can a lens be "pimped out" to be sharpest at its widest aperture?  (Read 4709 times)

texshooter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 575

I expect not, but I'll ask anyway. Is it possible to have a lens customized so that it is sharpest wide open? If so, why are there no specialized lenses sold that are geared only for wide open use? I certainly would buy such a lens. I guess physics won't allow for it. I would love to have my 135mm f2 hot rodded.
Logged

Slobodan Blagojevic

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 18090
  • When everyone thinks the same, nobody thinks
    • My website
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #1 on: February 01, 2015, 02:01:34 am »

Most long telephoto lenses are sharpest wide open.

HarperPhotos

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1309
    • http://www.harperphoto.com
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #2 on: February 01, 2015, 02:18:42 am »

Hello,

Nikon is rumored to bring out a new 135mm F1.8 G lens with VR soon. Which I can imagine will be very sharp wide open. The new Sigma 35mm and 50mm Art lens are very sharp wide open as well.

http://nikonrumors.com/2012/03/09/nikon-135mm-f1-8-lens-patent.aspx/

Cheers

Simon
« Last Edit: February 01, 2015, 02:21:44 am by HarperPhotos »
Logged
Simon Harper
Harper Photographics Ltd
http://www.harperphoto.com
http://www.facebook.com/harper.photographics

Auckland, New Zealand

ErikKaffehr

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 11311
    • Echophoto
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #3 on: February 01, 2015, 03:08:56 am »

No,

I don't think so.

Astronomical telescopes are single aperture but they are usually not very wide. Microscope lenses are also single aperture but they used to have astronomic cost.

It is possible to make lenses that perform optimally at maximum aperture, it is just very expensive. They used to say that a perfect lens is diffraction limited. I have never heard of a photographic lens that was diffraction limited below f/4.

It is not possible to "pimp out" a lens. One exception is to use a band pass filter, that can reduce/eliminate chromatic aberration. A simple case is a green filter on a monochrome sensor.

The best lens at 135/2 you can buy is probably the Carl Zeiss Apo Sonnar T* 2/135.

It improves very slightly when stopped down to f/4, but performs essentially near optimum at f/2.

2122 $US at B&H


As a small comment to Simon and Slobodan, there are quite a few lenses that are very sharp at full opening, but almost all improve a bit when stopped down.


Best regards
Erik

I expect not, but I'll ask anyway. Is it possible to have a lens customized so that it is sharpest wide open? If so, why are there no specialized lenses sold that are geared only for wide open use? I certainly would buy such a lens. I guess physics won't allow for it. I would love to have my 135mm f2 hot rodded.
« Last Edit: February 01, 2015, 03:18:58 am by ErikKaffehr »
Logged
Erik Kaffehr
 

LKaven

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1060
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #4 on: February 01, 2015, 03:45:48 am »

As I understand it, many of these premium lenses -- certainly the Nikon 14-24, but also I suspect the Otuses (Oti?) and the Sigma Art primes -- are designed with outsized image circles in order to improve MTF across the frame and at all apertures.

This is not the same as creating a lens that is /optimal/ wide open.  I don't know if that is possible in principle.  But as in case of the 14-24, it /is/ possible to create a lens that is sharp across the frame wide open.  The 14-24 improves somewhat when you move to f/4 and f/5.6, but not dramatically. 

Petrus

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 952
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #5 on: February 01, 2015, 04:55:50 am »

It would be easy to make a lens which is sharpest at full open, by making it a f/4 or something…

Making a f/1.4 or f/2 lens sharpest at full open would be prohibitively expensive.

"Pimping" an existing lens is not possible, simple as that. If it was possible to make it better with slight modifications, the manufacturer would have already done it during the design process. Applying tighter manufacturing tolerances would improve things but raise costs.

Would you want to pay $50000 for a f/1.4 50mm lens sharpest at full open? Could you find a few thousand other buyers also? 
Logged

dwswager

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1375
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #6 on: February 01, 2015, 12:52:12 pm »

I expect not, but I'll ask anyway. Is it possible to have a lens customized so that it is sharpest wide open? If so, why are there no specialized lenses sold that are geared only for wide open use? I certainly would buy such a lens. I guess physics won't allow for it. I would love to have my 135mm f2 hot rodded.

The simple answer is no.  While a lens can be designed to work very well wide open, it characteristics typicality will improve to a point as you stop down some.  Based on the physics each lens formula will exhibit performance.  Also, as I understand it, lenses that perform well wide open are 'over designed' compared to a normal lens and hence will be bigger and heavier than a normal counterpart.  Compare the size and weight of the 55mm Otus with the very good Nikkor 58mm f/1.4G.  The Nikkor is a great lens, but can't compete wide open, but it is much smaller and lighter.
Logged

texshooter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 575
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #7 on: February 01, 2015, 02:46:15 pm »


Making a f/1.4 or f/2 lens sharpest at full open would be prohibitively expensive.

Even if the lens were made with only one f-stop?
Logged

Petrus

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 952
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #8 on: February 01, 2015, 03:20:02 pm »

Even if the lens were made with only one f-stop?

That would be a nifty way of making a lens sharpest at full open…  And cheap.
Logged

LKaven

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 1060
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #9 on: February 01, 2015, 03:21:41 pm »

Even if the lens were made with only one f-stop?

Of course if a lens has only one f-stop, it is the softest at that aperture.  :-)

Telecaster

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 3686
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #10 on: February 01, 2015, 03:34:54 pm »

Even if the lens were made with only one f-stop?

Hehe…one of my Zeiss 50/2 Sonnars has frozen aperture blades, so it does have effectively one setting. Around f/2.5.  :)

-Dave-
Logged

Doug Peterson

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4210
    • http://www.doug-peterson.com
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #11 on: February 01, 2015, 03:50:32 pm »

I expect not, but I'll ask anyway. Is it possible to have a lens customized so that it is sharpest wide open? If so, why are there no specialized lenses sold that are geared only for wide open use? I certainly would buy such a lens. I guess physics won't allow for it. I would love to have my 135mm f2 hot rodded.

You should try a Phase One 150mm f/2.8 D lens on a full frame 645 digital back. You'll rethink what it means to shoot wide open :). Does it improve when stopped down? I don't know that it does when measured in any practical terms; it can already resolve razor sharp under 80mp of scrutiny wide open, so improvement while stopping down is not practically meaningful.

The Schneider 110LS and 240LS behave similarly spectacularly wide open.

You can look at the cost, size, weight, and limited number of consumers that pay the premium for them for some idea of why more uber-lenses aren't made.
« Last Edit: February 01, 2015, 03:55:18 pm by Doug Peterson »
Logged

Jim Kasson

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2370
    • The Last Word
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #12 on: February 01, 2015, 04:05:15 pm »

...why are there no specialized lenses sold that are geared only for wide open use? .

Here is a lens whose wide-open sharpness is close to as good as it is at any other stop:

http://coinimaging.com/printing-nikkor_105.html

Nikon made several other similar lenses; they were designed for making motion picture "prints" -- positives to be sent to the theaters.

Nikon also made lenses for exposing the photoresist on semiconductor wafers.  Some of the earlier ones that only had to image features on the order of a micrometer were designed for visible light. I would expect that they'd be sharpest wide open. I'm not sure that they had diaphragms, though. Might make great macro lenses.

The Rodenstock APO-Rodagon D 75mm f/4 1:1 is sharpest wide open:

http://coinimaging.com/aporod75-4var.html

Jim
« Last Edit: February 01, 2015, 04:09:07 pm by Jim Kasson »
Logged

kers

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4391
    • Pieter Kers
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #13 on: February 05, 2015, 06:43:51 am »

My 500mm f8 reflex Nikkor is sharpest wide open, but not very sharp ;)
Logged
Pieter Kers
www.beeld.nu/la

BernardLanguillier

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 13983
    • http://www.flickr.com/photos/bernardlanguillier/sets/
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #14 on: February 05, 2015, 07:48:11 am »

I don't see any difference between f2.8 and f4 on the Nikon 400mm f2.8 E FL nor on the Leica R 180mm f2.8 APO.

The Otus 55mm f1.4 is amazingly good at f1.4 (better than many a lense at f4), but not as good as it is at f4 so it doesn't count.

Cheers,
Bernard

Jim Kasson

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2370
    • The Last Word
Re: Can a lens be "pimped out" to be sharpest at its widest aperture?
« Reply #15 on: February 05, 2015, 09:01:57 am »

My 500mm f8 reflex Nikkor is sharpest wide open, but not very sharp ;)

I have a 500mm  f/5 Reflex-Nikkor that is sharpest when stopped down all the way to f/5.

Jim
Pages: [1]   Go Up