Kenko tubes

bren-escape · 01-05-2009, 11:04 PM

With all these spring flowers and insects I have been taking a few pics, but I dont have a dedicated macro lens - the closest I have is the sigma 18-50 F2.8 macro.

Reading searches I was wondering whether a set of kenko tubes on my sigma 50-150mm F2.8 might be a good move? how would this compare to a second hand Tamron 90mm for instance?

Any thoughts/experiences welcome

jomike · 02-05-2009, 5:24 AM

Kenko tubes are a cheap(ish) way of getting a taste of macro photography, and should work fairly wel on your existing lenses.
The way tubes work means that the shorter focal lengths benefit more from the effect of tubes than longer. A rule of thumb is tube length/focal length = magnification. So at 18mm, 68mm of tubes (a full set of Kenko) will give you nearly 4X magnification in theory. It is impractical though because your lens will have to almost be touching the subject, cutting off any light. It becomes more doable at 50mm, giving you just better than 1X magnification with a few inches working distance.

A dedicated macro lens such as the Tamron 90mm is easier to use and will give sharper results than tubes on a zoom lens, simply because it was designed for that purpose. Remember that you can use the tubes on a macro lens as well, and the formula no longer applies because of the design peculiarities of a macro lens. 68mm of tubes on a Tamron 90mm will give you about 2.5X magnification, up from the 1X that it does without tubes.

For the ultimate macro lens, there is the Canon MP-E 65mm which does 5X magnification out the box. The down side is that it will not focus further than a few inches, so cannot be used as a sharp portrait lens as other macro lenses can, and it is not cheap.

anthony566 · 02-05-2009, 9:10 AM

If you really want to do macro then I would go for the Tamron 90mm see the link below as there is one on evilbay at £44 with 7 hours to go

Tamron SP Macro 90mm F/2.5 Lens on eBay, also, For Other Cameras, Camera Lenses, Photography (end time 02-May-09 17:59:11 BST)

jomike · 02-05-2009, 10:12 AM

Quote:

Originally Posted by anthony566

If you really want to do macro then I would go for the Tamron 90mm see the link below as there is one on evilbay at £44 with 7 hours to go

Tamron SP Macro 90mm F/2.5 Lens on eBay, also, For Other Cameras, Camera Lenses, Photography (end time 02-May-09 17:59:11 BST)

Just be careful here, this is the older predecessor of the current Tamron SP AF 90mm f/2.8 Macro 1:1 Di Lens and can only go to 1:2 in standard form, it needs an adapter to go to 1:1 and I can't see any mention of an adapter in the ad. Not sure how easily available and what price these adapters are.

bren-escape · 02-05-2009, 10:13 AM

Thanks for replies. I was watching that one Anthony

bren-escape · 02-05-2009, 10:14 AM

Quote:

Originally Posted by jomike

Just be careful here, this is the older predecessor of the current Tamron SP AF 90mm f/2.8 Macro 1:1 Di Lens and can only go to 1:2 in standard form, it needs an adapter to go to 1:1 and I can't see any mention of an adapter in the ad. Not sure how easily available and what price these adapters are.

Ah, thanks for the heads up.

Mike.P® · 02-05-2009, 11:09 AM

I have that macro lens (as well as a few others).
It needs a 1:1 adapter which is basically a extension tube but I have to say that although it is manual focus only it is a superb lens. When used without the adapter its a 1:2 and is excellent for portraits .. with the tube a 1:1 macro and is super sharp. Its beautifully made as well, not like todays lenses.

Tubes on your Sigma 50-150mm should be reasonable though .. I tried mine on my SIgma 70-200mm f2.8 with very good results.

bren-escape · 02-05-2009, 11:51 AM

Thanks Mike - I think tubes will be the way to go for now to try and then if I got a macro lens later it sounds like the tubes can improve on that too.

bren-escape · 02-05-2009, 12:27 PM

how does the different mm thickness of tubes work?

Also is it a case of cheaper ones are unlikely to retain autofocus? although is that not a problem when doing macro?

Mike.P® · 02-05-2009, 12:38 PM

Basically the more you add the closer you can focus but this means the lens has to get closer to the subject each time.

Tubes are best used with a 50mm f1.4/1.7 as that seems about the right length/speed combination.

You will also need a external flash to get the most out of the tubes because of the working distance on camera flash will be obscured by the lens.

bren-escape · 02-05-2009, 12:43 PM

thanks again Mike.

Seen these on evilbay, any thoughts? When I searched on here I read a few comments on not making at difference buying cheaper ones.

CANON Macro Extension Tubes with Cover 4 EOS DSLR & SLR on eBay, also, Lens Mounts Adaptors, Camera Lenses, Photography (end time 02-May-09 15:28:16 BST)

Or is it best to stick to kenko?

Mike.P® · 02-05-2009, 12:53 PM

To be honest I have no idea about Canon tubes, mine have the electrical contacts which allow my Pentax to auto meter and set aperture via camera body (still maual focus), the one without are fully manual.
It depends on how happy you are using manual .. I previously had a set without the contacts and they worked just as well but were a bit of a pain.

At the end of the day I would say if the Kenko ones dont meter then go for the cheap option, you will probably find yourself buying a dedicated macro within a few weeks anyway when you get "the macro bug".

eddiewood · 02-05-2009, 1:04 PM

Quote:

Originally Posted by bren-escape

With all these spring flowers and insects I have been taking a few pics, but I dont have a dedicated macro lens - the closest I have is the sigma 18-50 F2.8 macro.

Reading searches I was wondering whether a set of kenko tubes on my sigma 50-150mm F2.8 might be a good move? how would this compare to a second hand Tamron 90mm for instance?

Any thoughts/experiences welcome

Keep an eye out on eBay for the Tamron SP 90mm f2.8 1:1 Macro. I have one for my Sony and it's great, not cheap though.

Mike.P® · 02-05-2009, 1:12 PM

Of course there is always the Raynox .. excellent quality and cheaper than auto tubes.

jradley · 03-05-2009, 10:28 PM

Quote:

Originally Posted by bren-escape

thanks again Mike.

Seen these on evilbay, any thoughts? When I searched on here I read a few comments on not making at difference buying cheaper ones.

CANON Macro Extension Tubes with Cover 4 EOS DSLR & SLR on eBay, also, Lens Mounts Adaptors, Camera Lenses, Photography (end time 02-May-09 15:28:16 BST)

Or is it best to stick to kenko?

Those cheap ones don't have any electrical contacts so the lens won't auto focus (not a real issue as auto focus is somewhat irrelevant) but also won't operate the aperture, which means you're stuck with manual metering and the widest aperture, whch really doesn't work well at all.

The Kenko ones will do AF and aperture. I bought a set of Ohnar tubes for my Canon which are very similar and a bit cheaper. They work, though I'm not convinced by the build quality. I am considering a Tamron 90mm Macro though already.

Cheers,

John

WibXL · 04-05-2009, 9:57 AM

Quote:

Originally Posted by jradley

Those cheap ones don't have any electrical contacts so the lens won't auto focus (not a real issue as auto focus is somewhat irrelevant) but also won't operate the aperture, which means you're stuck with manual metering and the widest aperture, whch really doesn't work well at all.

I tried some of the cheap tubes that you can get off of Ebay and as you say everything thing needs to be done manually which isn't a problem but being stuck with the aperture at the widest setting is.

Having to take macro photos with a f2.8 lens results in an incredibly shallow depth of field which might be ok if you're taking photos of flat objects from above but pretty much useless for anything else.

jomike · 04-05-2009, 10:35 AM

There is a workaround to the aperture problem with Canon lenses.

You put the lens on the camera with no tubes attached and set the aperture you want. Press and hold the DOF preview button and remove the lens. The lens will now be "stuck" at the aperture you selected. You can now attach the tubes and shoot. Every time you want to change the aperture you will have to go through the routine again.

The above applies only to tubes with no electrical contacts. Kenko tubes will work normally.

WibXL · 04-05-2009, 2:06 PM

Quote:

Originally Posted by jomike

There is a workaround to the aperture problem with Canon lenses.

You put the lens on the camera with no tubes attached and set the aperture you want. Press and hold the DOF preview button and remove the lens. The lens will now be "stuck" at the aperture you selected. You can now attach the tubes and shoot. Every time you want to change the aperture you will have to go through the routine again.

The above applies only to tubes with no electrical contacts. Kenko tubes will work normally.

Kicking myself for not even trying to find that out but if I had I wouldn't have bought a Tamron 90mm macro lens which I like very much.