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20×24 Ultra Large Format Photography

My primary reason for acquiring and using a 20×24 ultra large format camera is to make unparalleled world-class contact prints. Why else would anyone go to the trouble of using a massive camera.

If you have never seen a professionally created 20×24 ultra large format contact print of any type, then you are missing one of life’s finest treasures. The detail, presence, and x-factor of an ultra large format contact print is sought after by serious collectors for good reason. Not only are they rare and in limited supply, but the serious collector understand the skill and knowledge required to work in 20×24 format.

I don’t see how it can get any better than 20×24 ULF contact prints. I mount my contact prints with a 4-inch border making the final artwork an impressive 28″ x 32″ and they are truly impressive.

Edward Weston taught us how magical large format contact prints are and why they have no equal in terms of that special x-factor. Weston worked with 8×10 and the 20×24 is six times larger! 

As contemporary large and ultra large format photographers, we have never had more creative options at any time in history. Choosing the most difficult and demanding format typically takes a photographer decades to arrive at that decision, and then the learning curve and skill-building begins.

While making digital negatives up to very large sizes is possible, I don’t find that to be a workflow I want to pursue because a chemistry-based analog process renders light in a way that can’t be imitated or matched. 

The alternative to an analog workflow is to use a digital camera, software, and computer-driven printer. The endless software and computer upgrades, not to mention the nightmares associated with maintaining large format inkjet printers, I don’t find any of this desirable.  I don’t know how other photographers choose to create their work, and I have no judgments about any of it. I am committed to a pure handmade analog workflow for the rest of my life and have no interest in digital technology for my fine art photography.

Very few people in the world are actively creating 20×24 ultra large format contact prints of any kind making them increasingly rare and unique.

By the way, I no longer post on social media, so if you would like to be notified when I publish new articles, share new handmade prints, and other updates, you can join my personal newsletter.


Each photographer would have to answer the question of why 20×24 large format for themselves; however, I will share some of my personal thoughts with you and if you would like me to update this section with your ideas, just send me your comments and suggestions, and I am happy to post them here.

Before you purchase a 20×24 ULF camera system, I strongly encourage to make some 20×24 enlargements and mat and frame them as a proxy for your future 20×24 ULF contact prints. Make sure you love the aspect ratio, the size of the print, and so on. Buying a 20×24 camera is only a small part of your future investment. If you love your 20×24 enlargements, then you will lose your mind over 20×24 ULF contact prints.

First, I should mention that I love large and ultra large format contact prints, always have, and always will. Art buyers and collectors also appreciate handmade large and ultra large format contact prints.  It feels very special to be part of a very small and elite community of artists.

Maybe the thought of Weston making 8×10 prints in his simple but highly effective darkroom is part of the mystique and romance that got me started so many decades ago. Over time, I began to love all the parts of the workflow that digital photographers criticized.

I got my first 11×14 camera in 1983, and I was astounded by how much bigger 11×14 was over 8×10.  I didn’t realize that 11×14 is about 192% larger than 8×10; I just knew it looked much more substantial once I had the print matted and framed. 

The details in these contact prints were even more impressive and the “x-factor” of these bigger contact prints became very special to me. The detail and overall feeling of the larger contact prints are nothing short of impressive with the correct subject.  Little did I know at that time that I would eventually work my way up to 20×24.

By the way, I no longer post on social media, so if you would like to be notified when I publish new articles, share new handmade prints, and other updates, you can join my personal newsletter.

35mm equivalents for 20×24

A standard lens for 20×24 based on the film diagonal of 31.2 inches or 793mm. The crop factor for focal length and effective apertures is 0.0545.

Now that you know the crop factor for the 20×24, you can use it to figure out the effective focal length and apertures compared to 35mm.

For example, if you want to know the 35mm effective focal length of a 47 1/2 inch (1206mm) lens like the one to the left of this text, just multiply 1206 x 0.0545 to get the equivalent focal length of approximately 65mm.

I use 35 inch (889 mm) and 30 inch (762mm) lenses regularly as well and they are equivalent to 48mm and 41mm respectively.

It is difficult to compare focal lengths of vastly different formats and while the math makes us feel better, if you compare a 20×24 enlargement from a 35mm camera to a real 20×24 ULF contact print with the equivalent focal length, they feel worlds apart.

You can use the same crop factor of 0.0545 to calculate 35mm equivalent apertures too. For example, f/128 on 20×24 would be the equivalent of about f/7 on a 35mm camera.

To figure out the 35mm equivalents discussed above, we need to use the Pythagorean theorem as described below.

Crop factor = diagonal of 35mm film / ULF size film.

The diagonal of 35mm film can be calculated using the Pythagorean theorem, which states that the square of the hypotenuse (diagonal) of a right triangle is equal to the sum of the squares of the other two sides.

In the case of 35mm film, the width is 24mm and the height is 36mm. So, using the Pythagorean theorem:

Diagonal^2 = 24^2 + 36^2

Diagonal^2 = 576 + 1296

Diagonal^2 = 1872

Diagonal = √1872

Diagonal = 43.27mm (approx.)

Therefore, the diagonal of 35mm film is approximately 43.27mm.

You can use the Pythagorean theorem to manually calculate the diagonal of any size ULF film.

20×24 ULF Lenses

Before I cover some useful information about lenses for the 20×24 format, I strongly encourage you to be clear about why you “need” a specific focal length. Buying 20×24 lenses is no trivial matter and often a serious investment.

Just about any ULF 30-inch lenses and longer should cover 20×24 at infinity.  Remember that wider lenses can be used for close-up or macro work.  I do this extensively with my shorter focal lengths. For example, I have a 30-inch element for my TT Signature Pictorialist lens that covers at infinity, but I frequently use my 18″ and 24″ elements for closeup and macro work.

Regular (not the aluminum barrel versions) Artar 24-inch (wide angle), 30-inch (standard), and 35-inch (tele) lenses all cover 20×24, and they regular versions of these lenses are reasonably priced and generally available on eBay.  They are super sharp as well. 

I previously owned the 35″ and 47 1/2 ” Artar aluminum barrel extremely rare lenses and they are incredibly sharp. Truly world class glass if you want the ultimate sharp ULF contact prints. I am currently exploring the exact opposite of sharp with soft focus Pictorialist lenses.

The 450mm Nikkor M F9 will barely cover at infinity if you stop down to f/45, but the image will be very soft on the corners, which is not always a bad thing. When you stop down to F90 and F128, you have yourself a wide-angle lens on 20×24 in a Copal 3 shutter.

The 450mm Nikkor is equivalent to about 24mm and a great wide-angle lens, but in reality if feels much wider on 20×24.

The Zeiss Jena 450mm F9 copy lens can be found occasionally on eBay for less than $500 typically, but it has limited application in my mind.

The 550mm Schneider XXL will cover 20×24, but it’s crazy expensive and wonderful if you can find one and are willing to pay a ridiculous amount of money.

Brand new Cooke Series XVa Triple Convertible (expensive $4k range in Copal 3)

Cooke XVa Focal lengths: 645mm (25″) (front cell only), 476mm (back cell only), 311mm (front + back)

The 645mm (25″) will cover 20×24, 476mm will cover 14×17 or use for closeup work, and 311mm (will cover 8×10 and also a great closeup/macro option) 

The 600mm Fujinon C will cover but not with very much movement, and its known to be soft in the corners.  These lenses are becoming very pricey.

600mm APO Nikkor will cover but not with very much movement and soft in corners

1000mm and 750mm Germinar single-coated lenses will cover at infinity.

750mm Nikkor Process lens (hard to find now)

30 inch Dallmeyer Rapid Rectilinear (good luck finding one)

Nikkor 480mm F9 APO Process Lens (Nikkor APO PDF)

Soft Focus/Pictorial Lenses

Tri-Tran 30-inch Signature Pictorial Lens (link)

20×24 Lens Guide Published by Wisner in 2007

LensFocal lengthMM ….InchesDegrees on 20×24Availability
Goerz/Zeiss Hypergon1506.0138.1very rare
Zeiss Series V Protar27510.8109.9very rare
Zeiss Series V Protar32512.8100.7very rare
Zeiss/B&L Series V, IV Protars39015.490.3rare
Goerz Am. Opt., Series III Dagors42016.586.1sometimes available
Goerz Dagors, Zeiss VII Protar48019.078.5sometimes available
Zeiss VII Protar59023.267.2available but can be $$$
Goerz American Optical Company Dagors61024.065.5rare
Zeiss Series V Protar63225.063.7rare
Zeiss VII Protar69027.259.2sometimes available
Goerz Apo Artar76030.054.6generally available
Goerz Apo Artar89035.047.6$1,000 on eBay 8/21
Turner Reich91536.046.4$884 on eBay 8/21

General Purpose Lenses To Consider

  • B&L Extra Rapid Universal Series D 22 3/4″ F6
  • B&L Special 30″ 700mm F6.3
  • Carl Zeiss APO-Planar 32″ 800mm 
  • Carl Zeiss Protar 24″ 600mm F7.2
  • Goerz (Berlin) Dragor Series III 30″ 750mm F7.7
  • Voightlander Collinear 24″ 600mm F6.3


Buying 20×24 B&W film is a once-per-year event that will make you cry if you miss the annual Ilford ULF film order and even if you don’t miss the order window, you will cry when you look at your bank account.

You don’t have to use film… 

Paper negatives are a great option for negatives with no compromises, in my opinion.  Ilford Warmtone Fiber Semi-Matte is my preferred ULF negative.

By the way, I no longer post on social media, so if you would like to be notified when I publish new articles, share new handmade prints, and other updates, you can join my personal newsletter.