Can you still use your lens normally with an extension tube on?

With 250mm, you'll need more mm of extension. The 3-tube set is best. As far as those tubes (that Zakna linked to) look like they have plastic mounts. Yes, the price is nicer, but i wouldn't suggest "cheaping out" with totally plastic tubes.. a metal mount is much more durable and strong. Tubes can last you a lifetime, and can be used with all lenses.. would you feel comfortable having a $1000+ lens(which you may eventually get) mounted on a plastic mount?

rick_reno wrote in post #14715207
A knowledgeable fellow in the macro section recommended Polaroid tubes, they're about $75 on Amazon. I've seen his photos, they're really amazing.

http://www.amazon.com …ywords=polaroad​+extension

Inspeqtor wrote in post #14717739
Rick,

Thanks for the suggestion and link. I have had the Kenko tubes in my wish list for awhile now. The Polaroid price of $75 sure beats the Kenko price of $199!

1Tanker wrote in post #14718189
With 250mm, you'll need more mm of extension. The 3-tube set is best. As far as those tubes (that Zakna linked to) look like they have plastic mounts. Yes, the price is nicer, but i wouldn't suggest "cheaping out" with totally plastic tubes.. a metal mount is much more durable and strong. Tubes can last you a lifetime, and can be used with all lenses.. would you feel comfortable having a $1000+ lens(which you may eventually get) mounted on a plastic mount?

I now have a question about the Polaroid tubes that Rick gave the link to... do they have metal or plastic mounts? The images on Amazon look like metal but I want to be sure. Thank you

Inspeqtor wrote in post #14718230
I now have a question about the Polaroid tubes that Rick gave the link to... do they have metal or plastic mounts? The images on Amazon look like metal but I want to be sure. Thank you

I looked and also Googled around for them, and nobody mentions it. I can't say for sure, but the mount between tube and camera is metal, so i assume the body to lens mount would be too.

Edit: You could always keep an eye open for a used set of 3 Kenko's ; there might even be some for sale on this forum.

What about the Tamron 90mmn 2.8? Best of both worlds??

Earwax69 wrote in post #14718396
What about the Tamron 90mmn 2.8? Best of both worlds??

This Tamron lens is a good lens. Most likely better than most normal lenses with extension tubes in terms of IQ.
But with fast lenses and extension tubes one can get very special images, with very shallow DOF (but not best IQ).
I love to use my converted Minolta Rokkor 58mm f/1.2 wideopen with extension tubes.
Most times with my DIY made 8 mm thick extension tube, but with 12mm there are even some good images possible.

Absolutly gorgeous photo ZoneV!

I think the Tamron 90mm is indeed a good idea. 360$ is not too much. However what's bother me is that it is somewhat the same lenght as my 85mm 1.8. Maybe I could sell the 85mm but it's one of my favorite lens!! Mmmm first world problems!!

I could also get the Kenko set in the future, If I really enjoy macro.

I agree that the price of the Kenko set is kind of high, but I did manage to buy a used set on this forum about 6 months ago for $110, so you should check the used section, Earwax.

You've already gotten your answer, but if I may add, macro photography added a whole new perspective to things and for me, was a really fun and exciting aspect of photography. It was well worth the money I spent on the set and it's great that now all of my lenses are macro lenses.

It's not my style of photography, and my tubes rarely get used, but they're great to have and they expand the limits of my gear. They were a good purchase for me.

As I am not a macro enthusiast, I simply wanted extension tubes which would permit occasional closer focus than provided within the lens' own focus mechanism, closer than the usual MFD.

I paid only $58 including shipping, got three Meike tubes with electrical contacts on eBay, like this one
http://www.ebay.com …ss_RL&hash=item​19d3b61f90
Both AF function and aperture control work with the Meike extension tube, and they both continue to work even if all three tubes are stacked on each other. Some folks report that if you use more than one cheapo tube, the communication between lens and body breaks down...but my tubes continue to function even stacked.

The non-metal mount feels fine on my sample, as well.

To answer the question posed in the OP...
In the days before AF, a lens would focus close by racking outward (away from the focal plane) the entire lens optics via the internal focusing threads. An extension tube merely displaced the optics even further away. But because the optics started off by being farther out by at least 10-15mm farther than usual (without extension tube), the ability to focus at Infinity (when the lens is at its FL distance away from the focal plane) was lost due to the use of the tube. With AF lenses, we do not necessarily SEE the optics (and the rear element) move away from the focal plane at MFD, so it is not as obvious how focus works with a lens.

I've been thinking about buying one but didn't know how practical they were. Does anyone one have anything good or bad to say about them?

Sparkeyluv wrote in post #14871055
I've been thinking about buying one but didn't know how practical they were. Does anyone one have anything good or bad to say about them?

Pro:
- They do what they're designed to do, increase magnification.. and they do it well.
- They can increase the maximum magnification (MM) of any lens you own.(if you buy the right set.. one that works for EF and EF-S lenses.. if you own EF-S lenses{crop})
- They can bring down the MFD to more manageable lengths, on really long lenses that have ridiculously long MFDs.(ie. 300/400 or longer lenses)
- They're relatively cheap (and definitely light), for what they can do.
- There is no glass to clean or worry about dirtying/scratching, etc.

Con:
- They will eliminate the lens' ability to focus to infinity.
- They have to be with you ( ie: carried in your bag, and installed) to get the required result.
- While they don't give a "defined" loss of light, as with a teleconverter.. you do still lose some light with them.
- Their effect is more noticeable on shorter focal-length lenses... the longer the lens, the more extension needed, for similar increases in magnification.( often impossible to reach high MM with long lenses {ie. 300mm}).
- With shorter lenses (ie. 50mm), minimum focus distance(MFD) can become impossibly close, if too much extension is used. ( this is why the 3-tube set is so great, you can vary your extension from 12mm to 68mm).
- One more thing to carry in your bag.
- DoF becomes extremely shallow, especially with short lenses (ie. 50mm), but this isn't the tubes "fault" per se, just a result of such close working distance.

All in all, i think they're very much worth buying, even though the Con's list looks bigger.

1Tanker wrote in post #14871161
Con:
- While they don't give a "defined" lose of light, as with a teleconverter.. you do still lose some light with them.

The 'loss of light' is caused by the fact that the image circle spreads itself larger as the lens is moved farther from the focal plane. So fewer photons Fall within the frame area (unlike a teleconvertor, where the FL is changed but the diameter of the aperture is not...so the f/stop gets truly smaller).

Usually, below about 0.15x we need not bother with 'loss of light'. At about 0.2x we need about 0.5EV more exposure, and at about 0.3x we need 1.0EV more exposure -- but TTL metering deals with that issue for us, and we only need to consider the loss of light if using a handheld meter!

@RAH1861: Thanks!! I got my Tamron 90mm macro now...

The Kenko tubes where 200$, the lens 350$. I couldn't be more happy with the lens.

Glad to hear you got the Tamron lens, Earwax. I have a Canon 60mm macro lens myself. Kind of wish I'd gotten a 90 or 100 as you did, but anyway, macro lenses are definitely the way to go for pure macro photography.

Earwax69 wrote in post #14872487
@RAH1861: Thanks!! I got my Tamron 90mm macro now...

The Kenko tubes where 200$, the lens 350$. I couldn't be more happy with the lens.

Now all you need is extension tubes to uses with your macro lens.