Extension Tubes...

[MrKickalot]

I have been inspired by this picture and others on usefilm.com.

http://www.usefilm.com/image/492754.html

I want to do some macro on a budget so I am looking at extension tubes. Anyone have any recomendations on what to buy? I am looking at this set:

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=71515&is=REG

Seems like a pretty good deal getting 3 for $129. If I am reading the bottom right I will still have autofocus on all my lenses because they all have a max aperture of f5.6.

As always thanks!!!

[DaveG]

I have been inspired by this picture and others on usefilm.com.

http://www.usefilm.com/image/492754.html

I want to do some macro on a budget so I am looking at extension tubes. Anyone have any recomendations on what to buy? I am looking at this set:

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=71515&is=REG

Seems like a pretty good deal getting 3 for $129. If I am reading the bottom right I will still have autofocus on all my lenses because they all have a max aperture of f5.6.

As always thanks!!!

When you use extension tubes you will have some exposure compensation to make because of bellows factor. A bellows is just an adjustible extension tube - more or less - and bellows factor for close up shots is something that large format photographers deal with every day. The farther the lens is away from the sensor, the less light will hit that sensor, so it has to be accounted for.

If you use the meter in your camera this factor will be taken into account. I mention this as your f5.6 lenses will not transmit the same amount of light with the extension tube mounted and that might mess up the AF. Each tube will have it's own bellows factor and then more factors as you stick them together. Even if you end up using manual flash or a handheld light meter then it's OK as long as you keep checking your histogram, and increase your exposure based on that. But the AF on a 10D is probably going to be affected by the lack of light coming through the lens.

I kind of think that AF in a macro situation is moot anyway, since that's an area of photography that lends itself to a slower shooting workflow. I've got the older non USM 100mm macro and although it has AF I never use it.

You will lose your infinity focus while the extension tube is mounted. This isn't the end of the world but it can be annoying if you are doing a walk about and want to shoot macro and full distance images without changing things.

If you do plan on shooting a lot with extension tubes you should see if you can get a macro focus rack. The camera mounts on this rack and then the rack is fastened to a tripod. Then you focus by moving the camera in and out on the focus rack. This is a lot easier than trying to nudge the tripod in and out a couple of mm.

[SeanDempsey]

I use this Novoflex focusing rack

http://www.adorama.com/NVFRM.html?searchinfo=novoflex%20rack&item_no=1


Once you use it for 1x or greater than 1x macro work, you'll never be without it. It's really pretty essential.

It also works for doing panoramics, you can use it to center the lenses nodal point over the axis of rotation, gets rid of parallax effects when you stitch the pictures together.

[Scottes]

I use the Kenko set on a few different lenses. They feel kinda cheap, but they work great.

I have used the 36mm on my 100-400 L at 400mm f/5.6 ona 10D and have had no issues with Autofocus. Well, if I am at the extreme limits of focus distance - both near and far - then it will often hunt. But AF will function.

[CyberDyneSystems]

Extension tubes.. cheap and great! Get them.

Canon SLRs use TTL metering (through the lens) .. so as long as you let the camera do the metering... as opposed to using a handheld meter,.. you will NOT need to use any exposure compensation.

[robertwgross]

CDS, I agree. DaveG seems to believe otherwise.

Let's put it this way, if there is exposure compensation necessary due to the extension tube, it can't be very much. I've never used exposure compensation for this sole reason, and I have never seen any exposure error as a result. Maybe DaveG's equipment is a little different from ours.

---Bob Gross---

[Scottes]

I did a test once using a 36mm tube on a 100mm lens. I wasn't testing for exposure so i didn't save those numbers. Compared to the "same" shot with just the 100mm the tube image was off by about 2/3 to 1 stop. This was not compensation - the tube caused about 2/3 to 1 stop of light from getting to the sensor. The camera detected this and exposed both images correctly. It was just that the shot with the tube took about twice the shutter speed.

So tubes cause loss of light, but my 10D at least will automatically compensate for this.

[DaveG]

CDS, I agree. DaveG seems to believe otherwise.

Let's put it this way, if there is exposure compensation necessary due to the extension tube, it can't be very much. I've never used exposure compensation for this sole reason, and I have never seen any exposure error as a result. Maybe DaveG's equipment is a little different from ours.

---Bob Gross--- Although I don't have any extension tubes for my Canon, I do have the three tube extension set for my Mamiya Pro-TL. I just did a check and there is a one stop bellows factor when I have all three of these tubes aboard. Sure it's small per tube, but one stop is a significant error if you are trying to light the subject with strobes and are counting on a handheld light meter. And I think that this is on point since the original poster mentioned getting the three tube package.

I pay attention to these details and it's helped me over the years, especially with large format. If you want to put your head in the sand and to pretend that this isn't important is fine, but your exposures WILL be off.

But my original point was that it could take slow lens to where it would not autofocus. I didn't know if it would as that depends on the original speed of the lens.

[robertwgross]

Although I don't have any extension tubes for my Canon, I do have the three tube extension set for my Mamiya Pro-TL. I just did a check and there is a one stop bellows factor when I have all three of these tubes aboard. Sure it's small per tube, but one stop is a significant error if you are trying to light the subject with strobes and are counting on a handheld light meter. And I think that this is on point since the original poster mentioned getting the three tube package.

I pay attention to these details and it's helped me over the years, especially with large format. If you want to put your head in the sand and to pretend that this isn't important is fine, but your exposures WILL be off.

But my original point was that it could take slow lens to where it would not autofocus. I didn't know if it would as that depends on the original speed of the lens.

Somehow I had thought that we were in the Canon EOS digital forum, not the large format forum. I think DaveG is doing manual metering, and that would explain things.

---Bob Gross---

[CyberDyneSystems]

Were also into symantics to a certain degree.. "Compensation" on an AUTO TTL system means telling the camera to expose differently from what the camera thinks is right based on it's own TTL meter..

By DaveG's definition I guess the 10D is allready "Compensating" the exposure for the user automatically.

To me though that is not compensation.. as the meter guage will still be top dead center... untill I dial in compensation on my own.

The Camera is metering correctly what the shutter should be for the lens assembly in use. If this includes an extension tube .. so be it. These cameras will happilay and correctly TTL meter through a toilet paper tube... it does not matter to them what the electronics tells them aperture is.. etc..


This is not to say that the tubes don't effect exposure.. indeed they do You will loose light and thus shutter speeds will be slower.. but the camera adjusts exposure automatically, thus.. no compensation is required.

[robertwgross]

CDS, I agree completely.

I was thinking about exposure compensation in the context of a Canon EOS digital camera. DaveG was thinking in the broader sense of the term.

The amount of time that I shoot in Manual mode is far less than 1% of everything I shoot, so I don't have to think that way much.

---Bob Gross---

[CyberDyneSystems]

CDS, I agree completely.

....

---Bob Gross---

Scary... :? :lol: :lol: :lol: :lol:

Is this one of the signs of the apocalypse or what? 8)

[MrKickalot]

Wow!! Didn't know I would spark such a debate!! Thanks for all the help!! I'm selling stuff as we speak to get them!! Thanks again!

[MrKickalot]

Well there on order!! I should get them Thursday or Friday(B&H is quick)!! I'll post a picture or two when I get them!! Thanks again for all the advice!!

[Tom W]

the great thing about these kinds of debates is that they are so full of knowledge. Congrads on your tube purchase. I have a couple myself, and use them occasionally.

[DaveG]

Although I don't have any extension tubes for my Canon, I do have the three tube extension set for my Mamiya Pro-TL. I just did a check and there is a one stop bellows factor when I have all three of these tubes aboard. Sure it's small per tube, but one stop is a significant error if you are trying to light the subject with strobes and are counting on a handheld light meter. And I think that this is on point since the original poster mentioned getting the three tube package.

I pay attention to these details and it's helped me over the years, especially with large format. If you want to put your head in the sand and to pretend that this isn't important is fine, but your exposures WILL be off.

But my original point was that it could take slow lens to where it would not autofocus. I didn't know if it would as that depends on the original speed of the lens.

Somehow I had thought that we were in the Canon EOS digital forum, not the large format forum. I think DaveG is doing manual metering, and that would explain things.

---Bob Gross---

Somehow I thought that you understood that the principles of large format photography often apply in other formats as well. Just because this is a Canon DSLR site I don't think that I have to dumb down my answers to make anyone happy.

The very first line in the second paragraph of my response was this:

"If you use the meter in your camera this [bellows] factor will be taken into account."

So many DSLR users will never notice that their meter has automatically compensated for the extension factor. As well you can always get to the right answer by careful review of the histogram. And I've said more than a few times that spot or incident meters don't make much sense to me (other than for calculating flash lighting ratios) anymore since review is so much better than prediction.

But how would you account for this if you used studio strobes? Would you ignore a one stop exposure error? And guess what, if you use the Canon 100mm macro lens at 1:1 I guarantee a bellows factor as well. As far as I'm concerned and it's nice to at least know that it's there, so you're prepared for it.

[robertwgross]

Somehow I thought that you understood that the principles of large format photography often apply in other formats as well.

It's just that large format film examples are not the best examples in the Canon EOS digital forum.


But how would you account for this if you used studio strobes?

I've never felt compelled to use studio strobes. The Canon system works fine for me.

---Bob Gross---

[MrKickalot]

I said I would post a picture or two... here they are!!

http://www.fotop.net/allmanphoto/Macro_insects

Worth every penny!!