Stopping down a Canon EF lens
If you’re used to manual lenses, you know how easy it is to stop them down. If you are a little bit more advanced than that, and have ‘graduated’ to more advanced lenses, stopping down a lens (i.e making the aperture smaller) while it is not attached to a camera body can get a little problematic. There is a way to do it, however…
All of Canon’s newer lenses (actually, as far as I am aware, the whole EF and EF-S series) have electronically controlled aperture. Normally, that’s great, because you can select what aperture you want with the thumb wheel or via the camera’s menu system, instead of having to do it with a wheel on the lens itself.
There is a trick you can use to stop down lenses, however. Mind you, this is probably a bad, bad thing to do, and it may break stuff. Having said that, I have been doing this for years, and it seems to work fine, without any adverse effect.
Stopping down a lens is done by putting the lens on the camera, and setting the camera to either manual aperture (A or Av) or fully manual (M). Select the aperture you want. Then, press and hold the aperture preview button. If you don’t know where that button is, it is probably the one near the bottom of your lens, on the side. The one that you never use. Yes, that one. Press it, hold it, and then take the lens off the camera exactly like you would do normally.
If you have done it right, you are now holding the lens, which should still be stopped down. It should look approximately like in the picture with the red circle.
Finally, this trick for setting the aperture is not a “reccomended” method (not that there really is one), but at worst the “ERR 99″ or “ERR 01″ it may produce on the camera can be cleared up by turning the camera off and back on.
So why would you bother?
Well, this trick will come in most useful when you’re using your lens detached from the camera, obviously. This would come in particularly useful in macro photography, such as if you are using spacers between your lens, so your camera can’t send the right signals to the lens to make the aperture change.
If you are reversing your lens with a set of reversing rings, it would also be useful, if you want to use the lens at anything other than fully open.
And hey, it’s a nifty trick. Sometimes, that ’s all you need, right?
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Insights, suggestions and comments
ok, but why?
I’ve done it a few times to show people what changing the aperture actually does. Also good for Pringles can macro lenses and other things that make people in the business of cleaning dirty sensors very, very happy.
yeah, your story seems to stop half way. What is the purpose. Once I have taken my lense of my camera, I can’t take a pic, so what is the use. Develop your idea please. Paulp
Phil and Paul: I’ve updated the post a little bit. See also the Pringles macro lens, which was the base of this article.
The main reason I’ve posted this here, is that a lot of people find my website via google and other search engines looking for this particular information, so instead of having it hidden in a different article, it makes a lot of sense to have it posted separately too, don’t you think?
Wolever: Stopping down a lens and fitting it on the camera in a different way doesn’t have to add dirt inside the camera. Like everything else you do when there is a risk: Taking a bit of care, making sure everythign is squeeky clean, and paying attention to what you are doing goes a long way.
- Haje
Here it is nearly three years later than your post and I found your knowledge very valuable. Thanks much for keeping it available. You saved me big bucks by allowing me to use plain old extension tubes instead of the high-priced “guys”.
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