Effective Base Length - EBL

Most Accurate Rangefinder Camera? (Effective Base Length, EBL)

What is the most accurate rangefinder camera?

The answer can be determined by a value called Effective Base Length (“EBL”). EBL is calculated as the rangefinder Base Length (the distance between the 2 rangefinder windows on the front of your camera) multiplied by the rangefinder magnification. The higher the EBL value the more accurate your camera can be.

Effective Base Length = Base Length x Magnification

5 additional factors to consider when determining rangefinder camera accuracy

  1. How big and bright is the rangefinder? – The easier it is to see the better the accuracy can be
  2. Is the rangefinder patch defined with good contrast? Low contrast rangefinder patches are more difficult to see
  3. Is the design a combined viewfinder-rangefinder window? This is more accurate as you can near instantly focus-compose-shoot
  4. Does your camera have a diopter? If yes, you can micro adjust your view regardless of your eyesight prescription for better accuracy
  5. Lastly, and most importantly, is your camera rangefinder accurately calibrated? (If not, you need to fix that as the first priority)

Best Leica Portrait Lens?

Effective base length camera list (EBL)

This table lists many of the rangefinder cameras I’ve reviewed for the blog and on YouTube plus a few extra ones. See the film cameras reviews section for more on these 35mm film cameras.

CameraBase Length (mm)MagnificationEBL (mm)
Kiev 4900.872
Contax II/III900.7567.8
Leica M368.50.9162.3
Canon L3411.561.5
Nikon S260160
Leica M6 (0.85)69.50.8559
Leica iii391.558.5
Bessa T35.81.553.7
Leica M6 (0.72)69.30.7249.8
Leica M2/M4-P68.50.7249.3
Contax IIa/IIIa730.6648
Zorki 441141
Bessa R3A/R3M37137
Bessa R370.6925.5
Leica CL31.50.618.9
Data from Johnny Martyr post – See original post for more cameras

Special thanks

While doing my research on particular rangefinder cameras I found a great article by Johnny Martyr on EBL. The numbers I share in this post are from Johnny (some numbers vary slightly from other sources I found but they give you a good approximation). See Johnny’s post for additional cameras not listed above and for his take on the EBL topic.

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Leica Noctilux Photographer

Camera worth mentioning

After reviewing the effective base length camera list let’s look at a few specific cameras including the winners and losers.

The winners

Leica M3

If you’ve followed me for a while you’ll hear me bang on about why the Leica M3 is the best Leica film camera. Hopefully now you can see why. What matters the most to me is the camera is as accurate as possible for fast glass portraits. For this reason the Leica M3 is king (of Leicas*).

Kiev 4

You might also recall me speaking very positively about one low costs Soviet rangefinder camera. Without sounding like a broken record, now you can see why I love this camera. I don’t use these cameras just for fun (well I do that too!).. I use these cameras as they are at the top of the rangefinder camera tree. Brilliant camera and with the highest EBL value the Kiev 4 cameras are THE most accurate camera of those listed (including all mainstream cameras I’m aware of – original list).

It’s worth noting if you’ve not seen the Soviet camera videos I shared, the early dated Kiev 4 cameras were made from the Contax II/III tools and jigs. A very early dated Kiev camera is said to contain Zeiss parts. Despite both cameras looking nearly identical and having the same base length of 90mm, the Kiev has slightly higher magnification which makes it the number one. (I have a clean Contax IIIa camera which has a shorter base length and for that reason I use the Kiev instead for better accuracy).


The losers

Leica CL

If you’ve seen the YouTube video you’ll know I have a Leica CL (or Leitz CL) film camera. One of the cheapest Leica M cameras, small, light.. and completely useless for fast glass portraits. With the lowest EBL value this camera is your worst option (of those mentioned) if you want to attain accurate focus with fast lenses. It’s a great camera to use for street, travel or landscape photography just not the model portraits I do.

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Leica Noctilux f1 Portrait

Voigtlander Bessa R

Sadly most of the Voigtlander Bessa cameras are low on the EBL list with the except of the Voigtlander Bessa T (which is better than a new Leica M6 in terms of rangefinder accuracy). Bessa cameras are still great for non-portrait work like the Leica CL and the R3A/R3M is the best all rounder to include a few portraits (say with the Voigtlander Nokton 40mm f1.4 lens)

Honorable mention

Leica iii cameras

Despite their age, Leica iii cameras are more accurate than the new Leica M6 and all other Leica M cameras except the Leica M3 and the 0.85 M6 variant. Leica iii cameras also have a built in diopter for improved accuracy. If you don’t mind a small rangefinder/viewfinder window I love them.

Canon L3 (and similar models)

As you can see from the effective base length table, the vintage Canon L3 (and similar variants) is fourth on the list. These cameras offer 35mm, 50mm AND a very accurate RF option for longer or faster lenses.

Summicron 90mm Portrait

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When does effective base length matter?

It matters a lot for me as a model/ portrait photographer as I enjoy fast aperture lenses. If you shoot at f8 all day you can ignore this post entirely. EBL doesn’t matter in the slightest at higher f stops. When I shoot at f8-f11 for landscape photography I don’t even use a rangefinder. I scale focus (or zone focus), especially with 35mm, 28mm and wider lenses. The Voigtlander Bessa R and Leica CL are both small lightweight cameras so they are great to own for non-portrait work.

What lenses need a high EBL number?

Lenses with a small aperture number like f1.2 or f1.4 (especially if 50mm or longer) and longer lenses such as 90mm f2 or 135mm f2.8. See my lens review list section for all the lenses I’ve covered. On the Kiev 4 my most used lens is a Zeiss Sonnar 50mm f1.5.

For Leica cameras I have quite a few fast lenses. Some of the best examples include the Leica Summilux 50mm f1.4, Leica Noctilux 50mm f1.0, Leica Summicron 90mm f2 and Voigtlander Nokton 75mm f1.5.

In Summary – The best rangefinder cameras for the 4 lens mounts are

  • Leica M3 – If you use Leica M mount lenses
  • Canon L3 (and similar) – for Leica screw mount lenses (LTM/ L39)
  • Kiev 4 cameras – for Contax RF mount lenses
  • Nikon S2 cameras – for Nikon S mount lenses

Do you need to upgrade to a high effective base length camera?

If you continue to struggle to hit focus with your current camera then yes this might be a good time to try a camera with a higher effective base length. (Assuming your existing camera rangefinder is accurately calibrated*) If not then keep enjoying the camera you have.


Focusing help for Leica M camera users

Most Leica M cameras only have a 0.72x magnification viewfinder. For my eyesight that isn’t good enough to nail focus with fast 50mm lenses. There are 2 solutions to improve a Leica M film camera. The first option is my approach and that is to make the viewfinder magnification of the Leica M2, Leica M4-P and M6 Classic (the bodies I have) closer to the Leica M3 by adding a Leica 1.4x viewfinder magnifier. These screw-in magnifiers fit all Leica M cameras up until the Leica M10 which has a larger diameter viewfinder. There is also a 1.25x version. 1.4x is perfect for 50mm and longer lenses/ view. The 1.25x would better suit 35mm lens users I think.

Option two seems less common. I’ve only seen these once when I was in Dubai. Leica also make screw-in diopters for Leica M cameras. If you don’t have 20:20 vision or want to be able to see easier to focus fast lenses these will get your non-Leica M3 camera closer to a M3. The other solution is just buy a Leica M3!

Leica M240 High Key

Focus aids for digital Leica M camera users

If you use a Leica M8 or Leica M9 camera the only focus aid options you have is those mentioned above for Leica M film cameras. If you own a Leica M240, M10 or M11 (and all variants with LiveView) you can make use of an electronic viewfinder, aka EVF or Visoflex. There are different version available depending on which Leica camera model you use. See my KitList for links to the EVF options available.

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Make money with your camera (so you can upgrade to a higher EBL camera!)

After reading this article you might like the idea of upgrading to a more accurate camera. That means more money being spent on camera gear but no fear. See my latest eBook that gives you tips on how to make money with your photography. I bought all my cameras and lenses from money I made from photography (long before YouTube*) so if I can do it you can too!

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