Kenko DG Teleplus Extension Tube Set - Canon

[dinners]

I was considering these tubes at £83

http://www.onestop-digital.com/catalog/product_info.php?language=en&currency=GBP&products_id=226

At the moment I have no macro lens but from the lenses I have 0- I thought they might be worth trying with the 50mm 1:8

Unlike my 2X teleconverter (which makes the 50mm 1.8 a 100mm 3.6 these obviously have no glass so I wondered how tubes effect focal length and aperture ???

Secondly what kind of macro ratio would I be able to achieve ???

Thanks

Phil

 

[Dogfish_magnet]

You'll get about 1:48 with the 50mm - focal length is not affected but the minimum focusing distance is reduced and you'll lose a little light - IQ should be the same.

*Edited magnification for accuracy see below

 

[Canon Bob]

You'll get about 1:1 with the 50mm - .

A full set of Kenko's will actually give 1.48:1 but the working distance is a mere 41mm at this magnification.

Bob

 

[dinners]

You'll get about 1:1 with the 50mm - focal length is not affected but the minimum focusing distance is reduced and you'll lose a little light - IQ should be the same.

Thanks for that

Sorry if this sounds a bit dim - do the tube's particular lengths (12 mm, 20 mm, and 36 mm) make the 50mm a 62mm 70mm or 86mm or any combination of the three. ??

When you say loss of light - would it hamper autofocus on a 50 1.8 or on slower lenses ??

Reduced minimum focus distance - does that mean nearer or further from the object ??

 

[Dogfish_magnet]

Thanks for that

Sorry if this sounds a bit dim - do the tube's particular lengths (12 mm, 20 mm, and 36 mm) make the 50mm a 62mm 70mm or 86mm or any combination of the three. ??(

When you say loss of light - would it hamper autofocus on a 50 1.8 or on slower lenses ??

Reduced minimum focus distance - does that mean nearer or further from the object ??

The tubes will not affect the focal length, it will always stay at 50mm reguardless of the tube fitted but you minimum focus distance will vary with each tube or combinations of tubes (distance from the end of the lens to subject) and as the minimum focus distance alters so dose the magnification.

Autofocus will still work but its usually easier to use manual focus for macro - you move the camera forwards / backwards to focus.

Reduced minimum focusing distance = closer to end of lens

 

[HoppyUK]

Oops! Crossed post with DFM!

Thanks for that

Sorry if this sounds a bit dim - do the tube's particular lengths (12 mm, 20 mm, and 36 mm) make the 50mm a 62mm 70mm or 86mm or any combination of the three. ??

No, you will get different magnifications and different focusing distances with different focal length lenses. You'll get closer with more magnification with shorter lenses. Not sure if that's what you meant though.

When you say loss of light - would it hamper autofocus on a 50 1.8 or on slower lenses ??

With tubes, you lose one stop of light at 1:2 (half life size) and two stops at 1:1 (life size) and so on. This means that you can quickly run out of light with macro, especially as you generally need a high f/number to get any workable depth of field at all. That's why ring flash is popular, which also helps with camera shake which is a big problem at high magnifications.

AF isn't usually a problem as you won't be wanting to use it at very close distance anyway. It is easier to use manual and move your body gently back and forth to achieve optimum focus.

Reduced minimum focus distance - does that mean nearer or further from the object ??

Minimum focusing distance is the distance between the camera and the subject.

 

[dinners]

The tubes will not affect the focal length, it will always stay at 50mm reguardless of the tube fitted but you minimum focus distance will vary with each tube or combinations of tubes

Got you.

So it's like my 50mm is being moved forwards.

 

[dinners]

Thanks Hoppy

You can tell I'm a landscape person can't you lol


I just wan't to give macro a go and with a longer lens being on my list a macro lens isn't an option just now.

 

[HoppyUK]

Thanks Hoppy

You can tell I'm a landscape person can't you lol

I just wan't to give macro a go and with a longer lens being on my list a macro lens isn't an option just now.

Cheapest way to a lot of macro fun is the little clip-on Raynox DCR-250 macro clos-up attachment. It'll get you down to 1:1 for less than forty quid off Amazon. And you don't lose any light with close-up lenses

 

[dinners]

Cheapest way to a lot of macro fun is the little clip-on Raynox DCR-250 macro clos-up attachment. It'll get you down to 1:1 for less than forty quid off Amazon. And you don't lose any light with close-up lenses

Yeah - I'd been swithering over one - either a 150 or 250.

I've scanned through a few threads tonight and found opinion divided between Raynox / tubes.

 

[HoppyUK]

Yeah - I'd been swithering over one - either a 150 or 250.

I've scanned through a few threads tonight and found opinion divided between Raynox / tubes.

I use tubes as they give better quality. They also cost a lot more, eg Kenko £120, are more fiddly, and lose light.

I also have a DCR-250 which I bought purely out of interest. It has no right to be as good as it is! Raynox is not so sharp at the edges, so not suitable for critical work like stamps or coins, but for flowers and general stuff where a) the important stuff is usually in the middle, and b) three quarters of the frame is out of focus anyway due to lack of depth of field, it really turns in a very creditable performance.

Search the DCR-250 on Flickr and there are thousands of great examples.

 

[dinners]

I've seen some great raynox shots but I always wondered if they were attached to what were already good 'macro' lenses.

I'll have to see what results I can dig up for raynox on the lenses I have just now.