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I'm curious why do those kit lenses and 50mm primes, plus some zooms including all telephoto glasses have their aperture controlled electronically by the camera and some of them lack the aperture control ring? Is it for the automatic exposure controls?

I want to shoot in manual mode.

marked as duplicate by mattdm, Olivier, Community Jul 7 '17 at 0:09

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    I'm not sure what you're asking. Are you asking if it's possible to control the aperture of the lens at all (yes -- you can select the aperture with the camera and it controls the lens) or why the manufacturers have chosen this particular design (aperture controlled through the camera rather than with a direct control on the lens)? – David Richerby Jul 4 '17 at 10:21
  • I'm asking why manufacturers, sometimes, don't include aperture control ring – CV01HatsuneASD Jul 4 '17 at 10:46
  • TrevorTheManiac69 If you particularly want to have lenses w / aperture control ring, you might consider Fujifilm and Leica cameras, lenses. – David Barry Jul 4 '17 at 13:50
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I'm asking... why manufacturers, sometimes, don't include aperture control ring?

The basic answer is because an aperture ring on the lens is not needed to control the aperture of the lens with modern cameras.

Early old mechanical cameras with no electronics could not select and control the aperture, so the photographer had to do it. The simplest designs linked the aperture control on the lens directly to the blades in the aperture diaphragm. As cameras became more sophisticated and started including through-the-lens composing and focusing, built in light meters, and 'brains' that could compute exposure automatically, various mechanical linkages between the camera and lens were devised to allow the camera to read the aperture setting of the lens and (sometimes - depending on the camera's capabilities and the 'mode' selected) control the lens' aperture.

Most camera systems today use digital electronic communications between the camera and lens. There is a small motor in the lens that moves the blades in the aperture diaphragm and the motor responds to an electrical signal from the camera body that tells it when and how far to move. The aperture setting can be selected automatically by the camera or it can be selected by the user using controls on the camera body that communicate this setting to the lens at the appropriate time.

Even the few camera systems that still use a mechanical connection to move the aperture blades have electronic communication between the (current) lenses and (current) cameras that includes data about the lens' maximum aperture and the current position of the aperture ring. If the aperture ring on the lens is set to an 'automatic' setting (sometimes locking the aperture ring at the narrowest aperture is also the 'auto' setting) the camera can control the aperture via the mechanical linkage.

There are advantages to letting the camera tell the lens when to stop down and what aperture to stop down to over setting the aperture via a direct mechanical ring on the lens that controls the aperture position with no connection (either electronic or mechanical) to the camera:

  • Metering and focusing can be done with the lens wide open. This is particularly an advantage with autofocus, where a wider aperture allows faster and more accurate performance of an AF system. Even with manual focusing, the viewfinder is brighter and the depth of field is narrower when a lens is wide open. This allows easier and precise manual focusing.
  • The camera can select and automatically change the aperture based on selected parameters. In Shutter priority mode or Program mode the user selects the shutter time and the camera selects an aperture value that results in correct exposure as calculated by the camera's light meter. Even in Aperture priority mode or Manual exposure mode it is usually faster to move a control dial to change the Av than to move an aperture ring on a lens.

There are further advantages to the camera controlling the aperture electronically rather than mechanically:

  • More accurate and consistent exposure. The mechanical connections between cameras and lenses that were common when lenses had aperture rings are subject to several issues that can result in inconsistent exposure from one frame to the next or even inaccurate exposure for every frame. Mechanical linkages wear as they are used and need periodic calibration (both on the camera side and the lens side) to insure they are moving the aperture blades to the correct position. The levers in some cameras are prone to bending if a lens is incorrectly attached, resulting in incorrect aperture position for all succeeding shots made with any lens.
  • Faster performance. High frame rates in 'burst mode' can sometimes result in the camera going faster than a mechanical aperture linkage can keep up, resulting in exposure beginning before the aperture is fully stopped down, particularly when narrower apertures are selected. Colder ambient temperatures can also slow a mechanical connection to the point even a single frame may not be stopped down properly when the exposure is made. Electronically controlled apertures can be stopped down much faster. The camera can also be designed to confirm the position of the aperture before releasing the shutter. In addition to less lag due to mechanical linkages, the motor for each lens can be matched to the size of the diaphragm to which it is directly attached in each lens.

There are a few modern cameras, such as the Fuji X series, that put the control for the aperture on a ring on the lens. But in such cases the ring on the lens is often a fly-by-wire switch that communicates its position to the camera which then sends an electronic signal to the aperture diaphragm.

  • A mechanical lens' aperture will only close when the shutter is pressed (for -reflection cameras). There is usually a button on the lens for manually closing the aperture to get a preview for DOF. Focusing has always been under wide open. Sometimes you would see "AE" on aperture ring to allow auto aperture. So it is not entirely impossible to have a mechanical ring and auto aperture at the same time. Sometimes I found mechanical rings to be more convenient since I would remember where each stop is and setting aperture will be much faster than blindly rotating the dial. – yulunz Jul 5 '17 at 18:40
  • @yulunz That depends on the camera. Many older designs had the aperture ring directly linked to the diaphragm. This was before cameras even had reflex mirrors/TTL viewfinders, built in light meters, much less automatic exposure (AE). – Michael C Jul 5 '17 at 19:59
  • From my experience indeed the diaphragm and the ring is linked directly, but when you mount the lens (a turn), the lever on the lens' mount will be blocked, this will open the diaphragm so user can focus wide open. When there were no reflex mirrors, focusing is sometimes through another lens (rangefinders, TLR's), which is always bright. I think camera makers realize this from very early on - nobody wants to peek into a dim viewer and try to focus. @Michael Clark – yulunz Jul 5 '17 at 20:34
  • It totally depends on the system in question. Does your experience include every interchangeable lens camera system since the late 1800s? Particularly non-bayonet mount systems from the first half of the 20th century? – Michael C Jul 5 '17 at 20:36
  • That's why I said "I think". There might be counter examples, but it will be very rare. I'd like to know if you have one. @Michael Clark – yulunz Jul 5 '17 at 20:39
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There may of course be different reasons, but in general, dropping the aperture ring on the lens saves the manufacturer a usually unnecessary, mechanical element, the lens will be cheaper to build and if you only use the lens on a relatively modern camera body (say built within the last 10-20 or even 30 years), you will in most cases have the possibility to control the aperture with a camera setting without using the aperture ring. Many modern cameras even fail to work if you try to use the aperture ring on an equipped lens, instead of setting the lens aperture to 'automatic' to allow it to be controlled by the camera.

The only 'real' use for the aperture ring is if you intend to use the lens on older film cameras with only limited or no built-in light metering functionality. Many modern lenses are anyway designed to be used on crop sensor DSLRs (e.g. the DX lenses from Nikon) and can not reasonably be used on older film cameras, for which the aperture ring may have been requred for the lens to be fully compatible with all functions of the camera body.

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    In general I agree - the reason is to save cost and in most modern cameras the aperture can be controlled from the body itself. One exception of this is the Fuji X series where they have chosen to put an aperture ring as a control point on the lenses rather than on the body. This is a user interface choice which Fuji have made to have separate Aperture, shutter speed and ISO controls rather than a PASM dial and a control which switches mode. – John Jul 4 '17 at 15:32
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    It's perhaps worth noting that he aperture ring on Fujifilm X lenses is just another dial and doesn't actually mechanically change anything. – mattdm Jul 5 '17 at 3:38
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I think you are mistaken. Just because a camera doesn't have an aperture ring, doesn't mean that you can't control the aperture - it just means that you have to control it manually from a dial on the camera, not a ring on the lens.

This is definitely the case for Nikon G series lenses that don't have an aperture ring and Fujifilm lenses like the 27mm pancake that doesn't have an aperture ring.

Even on Nikons where you ARE using lenses with an aperture ring, most of the time (unless it's a Nikon where you can override this) it throws an error unless you put the lens in smallers aperture (e.g. f22) and control with the dial.

K

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It doesn't matter whether it's kit lens/prime/zoom/telephoto, it's the technology of the camera and lens design that the manufacturer chooses and decides whether to have/not have an aperture ring.

If camera is in Auto [A] / Programme [P] mode, then the camera automatically controls the aperture electronically to achieve what the light meter determines to be the correct exposure. Also, if the camera has a 'Shutter priority' mode [S] or [Tv], then the camera automatically controls the aperture electronically to achieve what the light meter determines to be the correct exposure.

But if you switch the mode dial/menu to Manual [M], then you should be able to control the aperture manually by one of the camera dials/menus (depending on make/model and settiong). Also, if your camera has 'Aperture priority' mode [Av], then you should be able to control the aperture manually.

Is your camera not allowing you to use M or Av? Could you tell us what camera you're using?

  • I don't have any camera yet but I'm planning to buy one. Something like a Nikon D3400 or Canon EOS Rebel T6i and cram in some vintage lenses on it. – CV01HatsuneASD Jul 4 '17 at 10:48
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    Although this has been accepted, I don't think it (beyond the first sentence) actually answers the question, which is about why there's no aperture control ring on the lens, not about how to control the aperture via the camera. Although it surely is the manufacturer's choice, why did they choose to do that? What advantages does it have? – David Richerby Jul 4 '17 at 11:17
  • @TrevorTheManiac69 you need a vintage camera to hold a vintage lens. When Canon came out with the EOS (in 1987) they introduced an entirely new lens mount, so older lenses are quite incompatible. – JDługosz Jul 4 '17 at 11:31
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    A one knob camera will need a button pressed to change aperture in M. Maybe you just need to find it. – JDługosz Jul 4 '17 at 20:50
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    @PeterTaylor Yes, you can change the Av when in manual mode with entry level NIkons. You just have to hold down the correct button while moving the control wheel. Read the manual to find out which button it is! OR read this answer. – Michael C Jul 5 '17 at 0:52
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Many entry level SLRs have a dual function wheel for aperture and shutter speed and sometimes second one for overall exposure (amongst other things). This requires you to select which value you want to control in manual or programme modes, in Av or Tv modes it will control which ever one is not set automatically.

I suspect that this is a feature to make things easier for novices as there is only ever one main setting to worry about in anything other than Manual mode. The downside is that it makes full manual shooting a bit more fiddly as you have use one wheel for both settings.

So to control aperture manually you first need to be in a mode which allows it an secondly set the function wheel to the right setting, exactly how you do this depends on the camera and the mode you are in, typically there is a button on the back which toggles between aperture and shutter speed.

Mid range cameras tend to have dedicated, separate wheels for shutter and aperture, although again they may be disabled or have a different function in certain modes.

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    This doesn't actually answer the question as now clarified. The question is asking why there's no aperture control ring on the lens, not how to control the aperture via the camera. – David Richerby Jul 4 '17 at 11:16
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One of the main reasons is, because only a minority wants to control the aperture on the lens. Imagine having multiple lenses and each lens got different kind of control elements. You control most of the settings on your camera and only some, very lens centred settings on the lens.

One other reason is, that the camera still focus while the aperture is fully opened. The camera needs all the light it can get to do so. Only in the moment, when you press the button the lens gets closed to the preferred value.

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