Close Focusing with Anamorphic Lenses

Once you’ve gotten comfortable with focusing an anamorphic lens, you may want to explore macro focusing to really bring out the character and bokeh of anamorphic cinematography.

Many anamorphic lenses need some help to close focus. Large format lenses usually have a minimum focus distance of around 10 feet/3 meters, while smaller Isco builds can get within 2-3 feet/1 meter. This should be one of the main considerations when you are choosing which anamorphic lens to invest in. Our custom single focus anamorphic lens can focus within 2 feet (0.6m).

To focus closer than your anamorphic lens has been built for, you have two options.

If you have a dual focus anamorphic setup

Dual focus anamorphic lenses work by first focusing the anamorphic lens, and then tweaking the prime taking lens that it is attached to. These lenses include the full and mid size Isco, Micro Isco, Sankor, and others. If you’d like to learn more about how to turn a dual focus anamorphic lens into a single focus, check out our guide.

If you wish to focus closer than your minimum focus distance, then your easiest solution is to use a diopter in front of your anamorphic lens.

What does a diopter do?

A diopter is a lens that magnifies your image by a set power. When used with a DSLR lens, a diopter will shorten your lens’s focus distance range (minimum-to-infinity).

For example, say you have an anamorphic lens setup that can focus from infinity to about 3 feet / 1 meter. If you add a +1 diopter to the front of the anamorphic, your focus range will now be adjusted to the following:

No Diopter +1 Diopter
Max focus Infinity 3 feet / 1 meter
Min focus 3 feet / 1 meter 1.5 feet / 0.5 meters

With a +1 diopter, your original maximum focus (infinity) will now be 3 feet, and your minimum focus will be 1.5 feet. Your lens will now focus between 3 feet and 1.5 feet.

No Diopter +2 Diopter
Max focus Infinity 2 feet / 0.5 meters
Min focus 3 feet / 1 meters 1 feet / 0.3 meters

With a +2 diopter, your maximum focus (infinity) will now be 1.5 feet, and your minimum focus will be 1 feet.

So when storyboarding and planning out your anamorphic cinematography, consider the focus distance of your subject, and be sure to have the diopters that you need. Since many indoor medium shots are consistently within the 2-5 feet range, be sure to purchase an anamorphic lens that can focus within that range, or the diopter power that will allow you to get to this range. For many cinematographers, a +0.5 diopter can be a very useful tool.

No Diopter +0.5 Diopter
Max focus Infinity 6 feet / 2 meters
Min focus 3 feet / 1 meter 2 feet / 0.7 meters

Where to buy diopters?

Decent quality diopter sets can be found inexpensively on eBay or Amazon. Inexpensive sets typically come in sets of four: +1, +2, +4, and +10. For most filmmaking, you likely won’t need the +4 or +10- those will only be useful for macro shots. Be sure to purchase the diopter kit in a large enough diameter to cover the full front diameter of your anamorphic lens- this usually would be 67mm or larger.

If you require higher quality optics, invest in an  Achromat diopters provide better quality standard closeup magnification lenses due to their two highly corrected optical elements, instead of just one. This corrects for imperfections and artifacts such as color fringing and edge softness.

The best anamorphic diopter investment would be a low-power (+0.5) achromat diopter- however these can be a difficult find. The following diopters work well for anamorphic shooting:

The Single Focus Technique

This trick works for dual focus anamorphic lenses that have been adapted to single focus using a rangefinder.

Dual focus anamorphic lenses focus by focusing both your taking prime lens and your anamorphic lens. While this technique is not hard to master, some filmmakers prefer shooting with a single focus setup. Instead of purchasing a single focus lens such as the Isco 36/54 or our custom single focus anamorphic, a more budget friendly option includes purchasing a dual focus anamorphic lens and then accessorizing with a rangefinder to the front of the anamorphic.

What is a rangefinder?

An anamorphic rangefinder is a set of two achromat diopters positioned in reverse polarity. Focusing is then achieved by varying the distance between the two diopters. For far focus, the two diopters are as close as possible, and for closer focus, the two diopters are separated, adjusting the power of the collective diopters.

Popular rangefinders include:

Once the rangefinder is attached to the front filter of your anamorphic lens (if your lens does not have a front filter, our custom clamp can help), set your prime taking lens to infinity, your anamorphic lens to infinity, and now your rangefinder will focus the entire system in one motion, from infinity to the minimum focus distance of the rangefinder.

The close focus trick is something we discovered through our own experimentation and use of anamorphic lenses. Instead of calibrating your prime and anamorphic lenses to infinity- pick what you need to be your own infinity. For example, if you set your prime and anamorphic lens to focus at say 10 feet, your rangefinder will now be calibrated to focus from 10 feet to a much lower minimum focus distance.

For details on how to achieve this close focus trick, see our close focusing anamorphic video and guide here.

As a rangefinder is a set of variable power diopters, this is the same optical concept but just adjusted by a different variable- the taking/anamorphic focus distance instead of a fixed diopter.

Of course, you lose your ability to focus further than 10 feet without recalibrating back to infinity. But this method is a great way of using rangefinders to eliminate the need for single diopters- and being able to achieve rack focuses within inches while still maintaining pristine optical quality- emphasizing the beautiful depth of bokeh of an anamorphic lens.

Summary

If you have found this article interesting and are further interested adding anamorphic to your toolbox as a cinematographer, please visit our anamorphic lens store for demos and examples. We have spent several years collecting, modifying, and testing anamorphic lenses to weed through the junk, make needed modifications, and assemble ready-to-shoot packages.

If you are interested in learning more on working with anamorphic lenses and DSLR, please check out our anamorphic tutorial blog for more anamorphic tips and tutorials!

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