I have a Rebel T3 and have been fooling around with it for several years using all the dial options, except the manual ones. I have read up and understand ISO Aperture and shutter speed—somewhat. I never needed to use them much until now.

I purchased a Vivitar manual telephoto lens. It came with typed instructions and I am having trouble understanding them. I put the camera in M mode and have been using the dials on the lens, but instructions are telling me to change the aperture and ISO. Do I do this with the camera menu, or on the lens? Or is it a combination of both? I have been adjusting both and gotten some okay pics but not what I want.

  • \$\begingroup\$ Which lens are we talking about? Is it a Vivitar lens designed for EOS or for a different camera mount you're using with an adapter ring? In what way is the lens manual? (i.e., is it a mirror lens that doesn't change aperture at all?, or just manual focus/aperture?) \$\endgroup\$
    – inkista
    Commented Feb 20, 2016 at 16:47
  • \$\begingroup\$ Good ? that is my question. It tells me to set one dial at 8 and then go up to adjust. I have found I get better pics with it set on 11. It is a a Visitor Series 1. \$\endgroup\$
    – Polly57
    Commented Feb 20, 2016 at 20:25
  • \$\begingroup\$ So you're using it with an adapter ring? \$\endgroup\$
    – inkista
    Commented Feb 21, 2016 at 1:56

3 Answers 3


Vivitar manual telephoto lenses have no electrical communication with the camera.

You can disregard any instructions that came with the lens because that lens was meant to be used on film cameras that had a mechanical connection to the camera for setting aperture.

When used on your T3, the lens has no communication, the camera will always read f/00 for the aperture. Aperture can only be set by turning the aperture ring on the lens itself. ISO can only be set on the camera,

Once you set the ISO on the camera, and select an aperture on the lens, you then have to find a way to set the correct shutter speed for a proper exposure.

You can set the shutter speed in Manual mode and use the exposure meter to get the correct exposure, or put the camera in Av mode (aperture mode) and let the camera select the right shutter speed. Even though the camera sees f/00 it will still attempt to select the correct shutter speed for a good exposure.

Tell us exactly which Vivitar lens you have and we can give you some tips on how to get the best photos from it.

  • \$\begingroup\$ What mount is it? What kind of adapter are you using to mount it on your T3? \$\endgroup\$ Commented Feb 21, 2016 at 9:58

You can adjust both Aperture and ISO on the Camera if the lens is electronically connected to the camera. If not then you can still adjust ISO since that's a camera function but not the Aperture.

If you're using an adapter and lens then its best to get lenses with Aperture rings for this very reason.

Again ISO though is always within the camera. And in my own view don't adjust ISO too much. I think of it still like Film, set the ISO once based on if I'm shooting street, portrait, night or daytime and then forget about it.


When using an adapted manual-focus lens on a Canon dSLR, you have to use either the M or Av mode on the camera. No other modes work properly, because the camera cannot tell the lens to change the aperture setting. Aperture must be adjusted via the lens's aperture ring, and ISO is adjusted on the camera body, as you normally would.

In M mode, the exposure compensation scale at the bottom of the viewfinder now acts as your light meter. The 'needle' does not automatically get set to "0" as it would in Av/Tv/P/Auto. You have to put the needle there manually using the aperture ring on the lens, or adjusting your iso and shutter speed on the camera body. "0" may not be 100% correct, but it's where your camera would have put the exposure in one of the automatic modes, and should usually be in the ballpark.

You also have to focus using the focus ring on the lens, and it may be difficult to judge accurate focus once the lens stops down, because in order to get accurate metering, the camera should be stopping down the lens to measure the amount of light coming in. You may want to set the lens to wide open and focus before you adjust the exposure settings. And if your adapter was chipped for AF confirmation you can also use the green dot lighting up to judge focus lock, but I found it variable on accuracy.

But chips vary. I had one once that reported EXIF and AF confirmation, but it screwed up the metering in the camera by faking that I had a lens that would be wide open for metering and stopped down for the actual exposure, and whatever I had set on the lens had to be compensated for on the meter (i.e., if I shot with an f/2.8 lens, and I wanted to stop it down to f/8 for shot, and I'd set f/8 on the lens, I had to make sure the meter showed me I was -3EV). I've had others (that reported EXIF (including the aperture setting used) and AF confirm or just AF confirm) that worked just fine with stop-down metering. So, metering is another variable to consider.

My recommendation, if all this is too confusing, is to start by shooting in M mode with an EF-S lens, so you get conversant with how it's all supposed to work and what the individual settings do to an image and to exposure. (Bryan Peterson's Understanding Exposure is also a good reference for this). And once that's all sussed out, try again with the adapted lens.

This is also why I tend to recommend getting native-mount autofocusing lenses. After adding in adapter cost and PITAness, going with a manual adapted lens is really only for the super-stubborn, collectors, and video folks. :)

See also: Can I use lens brand X on interchangeable lens camera brand Y?


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