Canon Close Up: Tube vs. Adapter

Tommyboy

I recently purchased an EF 50mm f/2.5 for my 350D.

To get 1:1 reproduction, should I purchase:

Canon Life Size Adapter

or

Extenstion tube EF 25II?

On my Rebel, the 50mm functions as an 80mm. Does that mean increased minimum focusing distance? The life size adapter gives me increased distance between the subject and the film plane. Is there light loss like a teleconverter? There's about a $100 difference between the two, both of which are expensive.

Any advice much appreciated.

gryphonslair99

To get true 1:1 macro I would purchase the Canon Life Size Adapter. Made for that lens. My personal choice however was the 100mm f2.8 macro. Already 1:1.

Tommyboy

gryphonslair99 wrote:

To get true 1:1 macro I would purchase the Canon Life Size Adapter. Made for that lens. My personal choice however was the 100mm f2.8 macro. Already 1:1.

The EF-25II doesn't give 1:1?

Yeah, I wanted a 100mm f/2.8. Heck, even the 60mm f/2.8 is 1:1 out of the box, but I'm on a budget and trying not to buy any more EF-S lenses to get ready for a full-frame purchase.

Got a good deal on lens on ebay. Lifesize adapters are a bit more scarce. B&H has the best deal, but it's substantially more than I spent on the lens. I'd love to find a used one.

ian408

Kenko extension tubes are another option.

A set of them would give you some flexibility too. Oh, and I should add a set is only slightly more expensive than one of the Canon 25's.

LuckyBob

Tommyboy wrote:

The EF-25II doesn't give 1:1?[...]

You know, I've been trying to figure out exactly how much extension tubes change the magnification factor for quite some time, which segways nicely into my suggestion to check out the Kenko extension tubes. They're around half the price of the Canon tubes, and a full set of them is only slightly more than a single Canon tube. The other advantage to the tubes is that they can be used on other lenses - I'm fairly sure the life size adapter can't. Tubes do cause a light loss, as do teleconverters, but although I suspect that the life size converter is some sort of tube/teleconverter and would also suffer from light loss, I've never seen this confirmed anywhere. This may be its sole advantage.

I've got the 100mm f/2.8 macro and the Kenko tube set, but I still have no idea how to calculate how much individual tubes change the overall magnification or light loss; anybody have any idea?

Edit: Ian beat me to it

Tommyboy

LuckyBob wrote:

. . . I still have no idea how to calculate how much individual tubes change the overall magnification or light loss; anybody have any idea?

I can't tell you a formula, but I have a Nikkor 55mm f/2.8 and the PK-13 extension ring (which I believe is 27.5mm) makes the lens 1:1. So it would seem an extension tube of the half the focal length renders a 1:2 macro at 1:1. In which case the EF-25II would do it.

I hate aftermarket stuff, but the Kenkos are tempting. They don't work with AF-S lenses, but I would be most likely to use them on my macro, my 85 f/1.8 or possiblly the 70-300. I'll mull it over. . . .

ziggy53

The LSA increases your working distance, while the extension tube will decrease it. If getting light to the subject or getting too close to the subject is/could be a problem, get the LSA.

gryphonslair99

For the life of me I can not find my extension tube conversion chart. This however is from Shutterbug Magazine.

[FONT=Helvetica, Arial][SIZE=-1]The degree of magnification depends on the length of the extension tube relative to the focal length of the lens being used with it. When the extension tube is the same length as the focal length of the lens attached to it (for example, a 50mm extension tube with a 50mm lens), a life-size or 1:1 reproduction ratio results: the image of the subject will appear life-size on the film. If the extension tube is longer than the focal length of the lens, greater-than-life-size magnification is achieved.

It is a good article on Macro. http://www.shutterbug.com/refreshercourse/lens_tips/172/index1.html

As [/SIZE][/FONT]ziggy53 said, you will lose light with extension tubes. Direct from Kenko:

[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular][FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Please Note;

1. When using extension tubes the lens will not focus to infinity. The focus range will be greatly limited to a very close focusing distance.
2. There is light fall off when using any extension tube, sometimes the equivalent of 3 f-stops of light is lost when using multiple extension tubes together. This light lost can affect the camera's ability to auto focus. Manual focusing is recommended should the lens begin to "hunt" (not lock onto the subject).
3. Canon EF-S lenses will not mount on the KENKO DG Extension Tube Set. These lenses include but not limited to EF-S 10-22, EF-S 17-85, EF-S 18-55, and EF-S 60mm Macro.

This is a great site for Macro photography.
http://www.macrophotography.org/index.php
[/FONT][/FONT]

ziggy53

A great discussion of extension tubes here:

http://photography-on-the.net/forum/showthread.php?t=19350


And our AIR, LordV, has some calculations for those interested:

http://www.flickr.com/groups/macro123/discuss/112332/