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TUTORIAL: Different Types of Lens Aperture Control

TUTORIAL: Different Types of Lens Aperture Control
TUTORIAL: Different Types of Lens Aperture Control



February 25, 2017

You buy a new DSLR/mirrorless camera. It comes with a kit lens. You get used to the looks and feel of how it works. Then while browsing shops for cheaper manual lens alternatives, you are shocked by peculiar designs you've never seen before. It excites you, it makes you curious. Those are vintage designs and you might probably have no idea of how they work. You might see some lenses with a ring at the rear part (aperture ring), while you can see some that have two aperture rings toward the front of the lens. But what are they, how to you use them? This guide aims to help shed some light on this matter.


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'G' or Gelded Aperture

If you are using a DSLR, it is likely you are using a 'G' lens. G stands for gelded, which means the lens does not have an aperture ring. Lenses made from the year 2000 onward are all G lenses. These lenses have electronically controlled apertures.

Pros
The aperture is controlled through the camera body. It's easier to look at the LCD in front of you and adjust the aperture through the camera body, instead of grappling the aperture ring in front of the camera and finding your way to the correct aperture value. The electronics allows automatic light metering to get you the proper exposure. This is also a cost-cutting move by companies that allow lenses to be sold at a cheaper price. (Less material = less expense.)

Cons
It has no aperture ring. When shooting videos, my Nikon D5200 cannot change the aperture while video is recording and in Live View. Gelded lenses can be used on both film and digital SLRs. But only those film SLRs with electronics. For fully manual SLRs like my Nikkormat FTn, there's nothing to control the aperture on the lens.

Tokina AT-X Pro 12-24mm f/3

Tokina AT-X Pro SD 12-24mm f/4
Tokina AT-X Pro 12-24mm f/4

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Lenses with Aperture Ring

I would like to classify 2 types under this category:

1) Fully manual lenses (no electronics) with auto diaphragm.
The fully manual lenses with 'auto diaphragm' allows the lenses to stay open at its maximum aperture even if you stop down to other values. Then it automatically closes to the value you set (eg, f/4, f/8, f/16, etc.) once you press the shutter button. All lenses nowadays have this auto diaphragm.

Nikon Series E 75-150mm f/3.5

Nikon Series E 75-150mm f/3.5
Nikon Series E 75-150mm f/3.5



2) AF lenses with electronic aperture control.
I'm referring to lenses with aperture rings like the one before, but this time, these lenses have electronics and capable of autofocusing. In the mid 1980s, at the dawn of the AF or autofocus era, lenses now came with electronic aperture control. These lenses still come with aperture rings but require you to lock to f/22 so that you can electronically control the aperture from the camera body (you will get an error if you don't lock at f/22). One might think that the aperture ring is useless at this point. If you mount the lens on fully manual cameras (can run without batteries), then the aperture ring comes handy. This is more flexible than the G lenses. My personal hack to use the aperture ring without getting an error on my DSLR is to put a tape over the CPU contacts, now it acts as a fully manual lens.

Tamron AF 28-200mm f/3.8-5.6 (71DN)

Tamron AF 28-200mm (71DN)
Tamron AF 28-200mm f/3.8-5.6 (71DN)

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Preset Aperture

These are very old designs. They were common until about the mid 1970s. You will always see two aperture rings toward the front of the lens (most lenses have the ring toward the rear part).

How does it work? You 'preset' the aperture value using the first ring. The second ring is used to manually open and close the iris/diaphragm. For example, you set the first ring to f/16. It gets a little hard to see through the viewfinder, so you use the second ring to let more light in. Then you close it before hitting the shutter button. This is the opposite of the 'auto diaphragm' that I have presented before.

In the age of digital, where cameras can now shoot videos, the second ring also has an unintentional benefit -- the de-clicked aperture ring does not make a clicking sound while recording and it minimizes the introduction of vibration.

The downside to this preset type is that it may be cumbersome to manually adjust the iris/diaphragm. Sometimes one might also forget to close it, resulting in overexposed photos.

Helios 44-2 58mm f/2 (M42 mount)

Helios 44-2 58mm f/2 (M42)
Helios 44-2 58mm f/2 (M42)


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Mirror Lenses

The last type of lens in this topic is the 'mirror lens'. In summary, these lenses work by using mirrors inside, which allows to bend the light so that the overall length of the lens can be cut in half. That's why mirror lenses are very compact. The only disadvantage is that the aperture is permanently fixed. For example, you see the typical mirror lenses in 300mm f/5.6, or a 500mm f/8. It's a little price to pay for the convenience of traveling a compact mirror lens, but you can easily adjust the brightness through ISO and shutter speed anyway.

Reflex-Nikkor C. 500mm f/8

Reflex-Nikkor C. 500mm f/8
Reflex-Nikkor C. 500mm f/8





Have you watched the video embedded in this post? It would be most helpful if you could watch the demo. I hope this lengthy post is able to help you. Please share if you find this article helpful. If you would like to add anything, corrections, or suggestions, feel free to post a comment below. Thanks!


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The Nikon D5200 as my weapon of choice.

Vintage lenses are my poison.

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