Macro - Teleconverter or extension tubes?

[Fedgrub]

I'm trying to decide whether the Kenko 300 1.4x or 2x teleconverter or the Kenko extension tubes would be more suited to my macro work. I am wanting to take it beyond 1:1 and get some really close up insect shots with my Canon 100mm 2.8 macro.

I've done a lot of Googling and reading but a fair few of the sites seem to contradict each other and I'm unsure which to order.

Does anyone have any experience with either of these, or know any useful information?

Thanks

[ameerat42]

Hi Fedgrub.
I'm always interested in Qs like this. Is your lens the L series, or the non-L? (There seem to be two versions.)
Well, whichever it is, you should consider what is likely to affect the lens more:
1. Shifting its operating parameters further than optimised (with extension tubes), or
2. possibly introducing some image degradation via non-matched optical elements (teleconverters)?

It's a tough one, and nothing short of some trying out would really tell.

I found a couple of useful refs for the lens type, and noted it can do 1:1 reproduction.

On THIS site, scroll to the close focus section and you will see some reproduction ratios with 12mm and 25mm extension tubes.
excerpt:

MM with 25mm Extension Tube 1.39-0.26x

That's 40% larger image with the 25mm tubes. I suppose you'd get about 60% more with the two quoted tubes.

There is no mention of teleconverters, but you'd get a straight doubling of image size with the 2x.

Good luck with your enquiries.
Am.

[old dog]

I think the ext tubes would be the thing. I have the 300 Kenko set and a 2x nikon teleconverter (manual) and I`d definitely go the ext tubes. I have put my tamron 90 macro on with the tubes and it works pretty well but you need to use a tripod. I have used my 70-300VR with the tubes and it works terrific. Hope this helps.

[Fedgrub]

Thanks, Am.

I think the ext tubes would be the thing. I have the 300 Kenko set and a 2x nikon teleconverter (manual) and I`d definitely go the ext tubes. I have put my tamron 90 macro on with the tubes and it works pretty well but you need to use a tripod. I have used my 70-300VR with the tubes and it works terrific. Hope this helps.

Is it true the teleconverter allows you to magnify the subject at the same distance, or shoot x times as far away and get the same size as you would without it, and the extension tubes allow you to focus closer to a subject?

If that's true, then wouldn't the extension tubes smaller focus distance make it harder to get close enough to a bug without scaring it, whereas the TC will allow you to achieve the same results from a regular distance (with small IQ degrading)?

[ameerat42]

...
Is it true the teleconverter allows you to magnify the subject at the same distance, or shoot x times as far away and get the same size as you would without it, and the extension tubes allow you to focus closer to a subject?

If that's true, then wouldn't the extension tubes smaller focus distance make it harder to get close enough to a bug without scaring it, whereas the TC will allow you to achieve the same results from a regular distance (with small IQ degrading)?...

Yes.

What happens is that the - say 2X - teleconverter doubles the linear size, X4 the area and X1/4 the light intensity. So you lose 2 stops of exposure value with a 2X converter: what looks like f/4 on the lens is in fact f/8. They just magnify the image.
Am.

Just saw your last bit. The degradation of image quality is there just because you are introducing another optical element. However, its effect may be LARGE, or SMALL, or even negligible. If the latter, you will not even notice/see it, as it will be masked by other factors that go to make up the picture, like resolving power of the sensor.

I've used both 2X converters and extension tubes. Each method has its +/-s. You may consider getting a set of each, esp. if you're going to get into it some. Also (if you haven't already) consider reverse lens attachment.

[Fedgrub]

Thanks. The more I think about it, the more I think I will get the tubes first and then the 1.4 TC next pay. I eventually want to use them together so I guess it makes sense.

Is this what you'd recommend?

[ameerat42]

You can use them together. Experiment a bit, then find what doesn't work so well. Low resulting light and very shallow depth of field are the bugbears of this sort of stuff.

[Bennymiata]

I've tried both tubes and converters on my macro lenses.
Tubes allow you to get closer, thus increasing the size of the object on the sensor, but you do have to get a lot closer to the subject, which in the case of insects, can be difficult.

With a 2X converter, it magnifys the object by a factor of 2, so it will magnify the subject, and still allow you the space away from the subject that you had without the converter.
I use a Kenko 300 2X converter with both my Canon EF-S 60mm and Sigma 150mm macro lenses, and it works fine on both, but autofocus is a bit hit and miss at macro distances.
The degradation in IQ is only a small one and not really much concern.

[crafty1tutu]

I used to use the Kenko macro extension tubes with a Canon 75-300 lens and this was great as you could stand back from the insects and therefore less likely to startle them. You can use them separately or together which can be hit and miss, especially if you don't use a tripod (I hate carrying them around). I used them for quite a while until I saved up to buy my Canon 180 mm 3.5 L series macro len - my favourite lens.