Aperture control with extension tubes and reverse lens

[shniks]

Do extension tubes allow you to adjust the aperture? Do some brands allow this and not others? I was looking at getting the Kenko ones, I know they allow AF but do they allow you to control aperture as well?

Also, I have read about reverse mounting a lens for macro, how would you control aperture if you did this?

Thanks in adavnce.

[foxbat]

Aperture control: The Kenko tubes allow it. The pass-through connections that permit AF also permit stop-down.

Reversed lenses: The arrangement is long lens mounted to the camera with short lens reversed on to the front of it with a macro coupler that screws into both filter threads. The magnification you get is approx mm of long lens/mm of short lens. e.g. mount a 135mm telephoto on the camera and reverse a 50mm on to the front and you have 135/50 = 2.7 life size.

You MUST use the reversed lens wide open otherwise you will get vignetting from the aperture blades and that's fortunate because you have no auto-control over it so the power-off 'default' of wide open will work. You have the same full control over the long lens as usual and you'll need it because f/22+ is pretty much where you need to be.

[Andy_T]

reversed lens:
I've been told that there's also a workaround ... mount the lens you want to reverse on your camera, stop it down and hit the aperture preview button. With the button pressed, remove the lens from the camera :shock:

I haven't tried this myself, as I think the method is a bit rough.
I rather use an old manual focus lens (e.g. M42, NOINK) that allows manual aperture control.

Best regards,
Andy

[René Damkot]

For reversing lenses, there is this (http://www.novoflex.de/english/html/co_ema.php)
Or look here (http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=007m6Z) for the DIY version :) (and a lot of opinions / ideas)

[Mitcon]

Theres also a expensive reversing adaptor you can buy from Novoflex that transmits all information, electrical contacts.

Have a look at http://www.novoflex.com/english/html/products.htm

[René Damkot]

Hey Mitcon, you didn't try my first link, did ya? ;)

[foxbat]

Agree about the old manual one for the reversed lens. I use an old 50mm f/1.4 that can be had cheaply on ebay and the f/1.4 provides lots of light for the telephoto. Having auto aperture for the telephoto is useful as manually adjusting the aperture ring can be enough to throw off your carefully set focus at very high magnification.

[Mitcon]

Doh !!! lol, sorry I read what everyone said. Missed the links totally René :oops:

[shniks]

Great info, thanks lot!

[ron chappel]

As you can see from the replies,there are two different methods to reverse lenses.

The normal reverse method is as andy describes,including the neat trick fro stopping down the lens.While this method works well it does have the major dissadvantage of making the fiewfinder very dark so focussing in difficult.
Ironically it's far easier to use an old manual focus lens reversed because you can control everything manually.

The 'piggyback' method described by foxbat is abit dodgey in my opinion,i have never satisfactorily got this method to work.While ideal for small digicams it gives huge vignetting with every lens combination i've tried.
On the plus side,this method does give full auto stop down,etc