Teleconverters are a great way to get some extra reach without having to drop some serious money for a 400mm+ lens. It can be an essential tool for many photographers who are constantly cropping in on their images, even when shooting with a crop camera and telephoto lens. In case you didn’t know, a teleconverter is a small lens element that attaches to your lens and increases the effective focal range, typically by a factor of 1.4x or 2x.

Also known as an extender, tele-extender, or a doubler (2x), teleconverters are an important piece of equipment for long lens photography… but is there a limit?





Teleconverter Stacking

“Okay… so if a 2x teleconverter can give my 200mm lens the field of view of 400mm lens, would a second 2x teleconverter make it an 800mm?”

“How about 1200mm, or even more?”

Today we find out just how far we can go with teleconverter stacking. High above the streets of New York City, tourists atop the Empire State Building become the subject of our teleconverter ridiculousness. I do not suggest conducting the following experiment unless you like image quality loss and possible breakage of your camera.

Experiment Breakdown

The distance from the lens on ground level in Madison Square Park to the 86th floor Empire State Building observation deck is approximately 900 yards (860 meters) or about 9 football fields.

Our lens is a Canon FD 200mm f/2.8 S.S.C manual focusing lens. The FD teleconverters are various brands from JCPenney (they had camera gear branded back in the day) to Canon. The camera is a Sony A6000 with a 1.5x crop factor because of the Sony APS-C sized sensor which will be factored into each scenario, starting with the first 200mm lens shot: 200 x 1.5 = 300mm.

300mm with No 2x Teleconverter

600mm with One 2x Teleconverter

Immediately the loss on contrast can be seen. Very usable image though.

1200mm with Two 2x Teleconverters

Contrast lowering still, and starting to look very muddy. Usable though I don’t know anyone who would stack two teleconverters for taking a serious image.

2400mm with Three 2x Teleconverters

Camera lens becoming very unstable. Difficult to focus, the slightest breeze from movements of footsteps in the snow cause the lens to wobble. The idea of the lens adapter or a connection on one of the teleconverters snapping off starts to set in. Have to put the shutter on a two second timer to allow movement to settle before taking the image.

4800mm with Four 2x Teleconverters

Impressed with the reach. Finally able to make out the motions of the people on the camera screen, wondering if I could possibly recognize someone up there if I knew them.

When using the digital zoom for focus assist feature, turning the lens as carefully as possible to pinpoint focus appears to shake the image at an almost unrecognizable rate, the slightest movements are amplified so that focusing takes a lot of effort. Evaluating the sag of the lens due to the teleconverter stacking, wondering if I should end at four. Shutter timer set to 10 second delay, still may have been wobbling slightly.

9600mm with “Five” 2x Teleconverters

As I rock the focus side to side ever so slightly, not only can I not tell in-focus from out-of focus, I cannot tell what I am looking at when using the digital zoom focus assist. Shaking violently, it takes every bit of the 10 second timer for the motion to settle.

It looks as if you’re viewing through a literally muddy lens. Highly visible sagging of the lens and stress on the lens adapter. One more teleconverter will surely push the rig to break somewhere along the way. It’s a guessing game at this point, no way to tell if I’ve got the best focus for the situation.

Crop Comparisons of 0 vs 5 Teleconverters

Here are crops of the same scene. The top is from the 300mm view with 0 teleconverters, and the bottom is from the 9600mm view with 5:

Verdict

You can see from the image above that the beginning and end results are overall comparable, especially in terms of sharpness. The vertical posts of the fence on the observation deck have a strange distortion in the 200mm image when compared to the image made with teleconverter stacking. I’m unsure what this is caused by, it’s possible that it was caused by heat from the 87th floor which is a mechanical floor for the building.

Anyway I hope you enjoyed this article and it confirmed for all of you what you already know; teleconverter stacking to 9600mm is ridiculous but a lot of fun.

Update: We shared a similar experiment back in 2010 that involved stacking Canon extenders to photograph the moon.

About the author: Jordan Lockhart is a photographer based in Manhattan and the man behind CameraPlex, a new website with camera news, tips, and articles. This article originally appeared here.