Extension Tubes

[flowerfacade]

Since you guys are so helpful answering questions, I have another. Tell me about extension tubes. When I told you I was getting a Canon Rebel XT and I wanted to take close-ups (kids, animals, flowers) a few of you recommended lenses (one of which I got and have so far enjoyed: Canon EF 50mm f/1.8 II).
One of the recommendations involved the use of an extension tube. I really don't know what that is or how to select one. I did not ask at the time because it was more than I wanted to know just yet. But now I want to know, so can anyone tell me about them and how to properly use an extension tube!!!?????
Laura

[/IMG]
Taken of my daughter with the above lens mentioned.

 

[Master Mason]

Basically they are maginifiers for your lens. They go between the body and the lens and to use a quick example. If you have a 2x extention on your 50mm, you now have a 100m if you have a 1.4x extention on your 50mm you now have 70mm. You will loss some f stop in the equation. So on my 70-200 f2.8 when I put the 1.4 in I have a 98-280 f4.0 If I had the 2x extention it would be a 14-400 f5.6

I only have the single one that I use with this lens.

 

[jann1033]

http://www.kenko-tokina.co.jp/e/P.10_11.PDF

if you go the extension tube route make sure they are autofocus...if they don't have the electronics, the electronics on your lens won't work either( ie focus,)
if you want a reasonable priced macro alternative..
i tried the manual focus e tubes...no go
i tried the macro lens fiter type lens, not better
i ended up with a phoenix 100mm macro lens...phoenix is not a brand i'd normally buy but it was rated good on a few forums as a reasonably priced macro lens..it looks like a toy and is a little soft but works well enough for me...maybe when my skills improve i'll get a better lens but for $150( ebay was around 100 but i wanted it for vacation so couldn't wait), it is fine for me( about what the tubes cost)
i haven't used it tons due to my tripod not being the easiest to adjust for macro but this is one of the few i have taken with the above lens...the ones i took with the manual tubes were unusable
pros and cons from others
http://www.shutterfreaks.com/Tips/ExtensionTube.htm
http://www.northrup.org/equipment/extension.htm

 

[flowerfacade]

These are helpful points to consider....especially the manual vs. autofocus. It would have been a long time before I figured that out, and I do see a large price difference too. I am interested in all everyone has to say! Keep it coming!
L

 

[MarkBarbieri]

Basically they are maginifiers for your lens. They go between the body and the lens and to use a quick example. If you have a 2x extention on your 50mm, you now have a 100m if you have a 1.4x extention on your 50mm you now have 70mm. You will loss some f stop in the equation. So on my 70-200 f2.8 when I put the 1.4 in I have a 98-280 f4.0 If I had the 2x extention it would be a 14-400 f5.6

I think that you are confusing extension tubes with extenders. You description is correct for extenders, but extension tubes are something different entirely.

Extension tubes are hollow tubes that fit between your camera body and your lens. Because they are hollow, there is really no optical difference between brands. As Jan1033 said, you really want to make sure that you get one that is compatible with your camera's eletronics. The Kenko brand extension tubes are popular because they work and they're cheap. Unlike buying a cheap lens, going cheap here isn't going to hurt your pictures.

The point of an extension tube is to let your camera focus closer than it normally would. If you wanted to take a closeup picture of a flower, your lens might normally focus only if the flower was 3 feet away. If you moved closer, you couldn't focus on it. The extension tubes solve that problem by letting you get the camera closer.

There are two other ways to solve this problem. The simplest (and most expensive) is to buy a "macro" lens. These are lenses specifically designed to be able to focus up close.

Another is to buy a close-up lens. Canon makes a Close-up lens called the 250D. You screw it to the front your normal lens and it allows you focus more closely. Because it screws to the front of your lens, you want to make sure that you get one that fits your lens diameter. You can get one bigger and buy adapter rings to fit it on, but if you buy one smaller, it won't work.

The advantages of the close-up lens and extension tubes over the macro lens are that they will work with all of your lenses and they are cheap. The disadvantage is that they are a bit of a pain. With either the close-up lens or extension tubes on your camera, you will lose the ability to focus at a distance. If you are spending a day shooting macro shots, this is no big deal. If you are walking through a garden and want some close-ups and some normal shots, you'll find yourself swapping equipment a lot.

Most people seem to prefer the extension tubes over the close-up lens. The reason most often given is that the close-up lens is glass and so it adds just a bit more degredation to the image. Personally, I prefer the close-up lens. I've never noticed any significant degredation and they are much easier to work with. The problem with extension tubes is that little things like zoom radically change your focus, so it's harder to get everything set the way that you want. I found that my zoom lenses work much nicer with the close-up lens and I have less futzing around to do.

One thing that you'll notice with the tubes is that they come in different sizes. The longer the tube, the closer you can get to the object you want to photograph. One cool thing about owning a set of tubes is that you can stack them. So if you have the common set of 3 tubes, you really have 8 different combinations of tubes that you can use to get just the distance that you want.

Another important thing to consider with macro photography is depth of field. The closer you focus to an object, the less depth-of-field you have. This can be a serious problem. It can be very difficult to get a flower shot with the front and back of the flower all in focus. You end up having to use a very narrow aperture. That means that you end up with a low shutter speed. Lower shutter speeds are a problem because if your subject moves just a tiny bit, you are so close that the movement will cause blurring problems.

The normal solution to not having enough light is to add a flash. The problem with mixing flash and macro photography is that your subject is often too close to the lens for the flash to work well. If you get really hardcore about macro photography, you'll end up buying a ring flash. It's a circular flash that fits around your lens.

I think I've prattled on long enough, so I'll leave it here.

 

[flowerfacade]

Mark,

That is a very helpful explanation. I am looking for extension tubes or a macro/close up lens because I think I miss some really neat opportunities for pictures because I try to get to close for my cameras to focus sometimes.

I do not however know what the extenders are that you are referring to.

Laura

 

[0bli0]

Laura,

the extension tubes Mark is talking about will not work for you for taking close ups of your kids or animals. they will, however, be very useful for flowers and bugs. the reason they're no good for your kids is you lose the ability to focus to infinity - or you'll be a little too close... here is a shot with @ 50mm with an extension tube

you could get an teleconverter, which magnifies the focal length of the lens (generally by 1.4x or 2x). so your 50mm 1.8 would become a 70mm (~2.8 max aperture). this will help you get a tighter image from further away.

but you can get pretty close with your 50mm - just rotate the camera to portrait orientation.
here is one @ 50mm

and here is another 50mm of both of the above kids together, back in landscape mode

 

[MarkBarbieri]

I do not however know what the extenders are that you are referring to.

An extender (also known as a teleconverter) has nothing to do with macro photography. It makes your lenses longer. They come in two flavors - 1.4x and 2.0x. Like extension tubes, they fit between your camera body and your lens. If you put a 200mm lens on a 2.0x teleconverter, it will be a 400mm lens.

There are significant downsides to teleconverters. First, you lose light. With the 1.4x, your shutter speed will need to be twice as long. With the 2.0x, your shutter speed will need to be four times as long. This is a rule of optics, so buying a really fancy teleconverter won't let you get around the rule.

Another problem with teleconverters is that they magnify all your lens shortcomings. The 2.0x will drag down even great lenses so that their quality is only fair. The 1.4x isn't quite so bad. I have both and almost never use the 2.0x.

A final problem is that they won't work with all lenses. They (at least the Canon ones) only with their longer lenses. You couldn't stick the 50mm lens on a 1.4x Canon extender.

 

[flowerfacade]

Wow! I love all this info!

ObliO, I mostly posted the picture of my daughter to express how I pleased I was with the lens that I had gotten after following Stephanie/Olaf’s recommendation.(and a relatively inexpensive one too!!) It is one of the best pictures I have ever gotten of my daughter who is quite difficult to photograph especially if she is looking into the camera. I think the effect of the blurred background is great. I had not actually considered putting an extension tube on that lens, but after looking at that eye that might be where I should use it. The pictures that I seem to blur are close-ups of a chocolate covered Krispy Kreme doughnut with sprinkles, or a cupcake, or a dog’s nose, or a flower. I especially like Jan’s picture of the rose with water droplets. These are the kinds of pictures I am looking to take. I don’t suppose I can be too specific on this board, but I just didn’t mention exactly what I was looking for, I guess.

Mark, your explanations are great and not too complicated; I appreciate that. In fact I appreciate everyone’s remarks because I continue to learn on this board all the time!!!

I love all the pictures you all share when answering questions like mine—especially when you tell specifically how it was shot and the type of lens used and so forth….so very, very helpful to me.

L

 

[0bli0]

it's a great photo of your daughter. it's very nicely lit and the subject 'pops'. the blurred backgrounds come from the wide aperture - often referred to as bokeh. in the case of your photo above, it was taken at an aperture of F/4. you can open it up even wider to blur the background even more. just remember at F/1.8, the depth of field (how much of the images is in focus) will get very shallow.

extension tubes are pretty cheap - especially on ebay. they can be quite a bit of fun. but they take patience, practice, and often a flash as you generally get very close. you will be able to use them with pretty much all of your lenses - each of which will give you different types of shots.

and i totally agree - Jan's rose shot is beautiful. it can often be hard to photograph red subjects because the canon cmos sensors are very sensitive to that wavelength and often cause a loss of detail. she's done a great job of composing the shot and lighting it nicely.

 

[jann1033]

Wow! I love all this info!

ObliO, I mostly posted the picture of my daughter to express how I pleased I was with the lens that I had gotten after following Stephanie/Olaf’s recommendation.(and a relatively inexpensive one too!!) It is one of the best pictures I have ever gotten of my daughter who is quite difficult to photograph especially if she is looking into the camera. I think the effect of the blurred background is great. I had not actually considered putting an extension tube on that lens, but after looking at that eye that might be where I should use it. The pictures that I seem to blur are close-ups of a chocolate covered Krispy Kreme doughnut with sprinkles, or a cupcake, or a dog’s nose, or a flower. I especially like Jan’s picture of the rose with water droplets. These are the kinds of pictures I am looking to take. I don’t suppose I can be too specific on this board, but I just didn’t mention exactly what I was looking for, I guess.

Mark, your explanations are great and not too complicated; I appreciate that. In fact I appreciate everyone’s remarks because I continue to learn on this board all the time!!!

I love all the pictures you all share when answering questions like mine—especially when you tell specifically how it was shot and the type of lens used and so forth….so very, very helpful to me.

L

what lens are you using when the close ups are blurred?

 

[flowerfacade]

Jan,
I had been using my Sony Mavica...which is one reason I got a new camera. I just wanted more out of my shots. The Mavica has been a great camera though, and I still use it. It is quite hardy! I have dropped it and such, and I let my son, 5, use it too now that I have a new one.
The close-ups with my Rebel were using the kit lens and 50 mm that used to photo my daughter. Now I am just trying to figure out how to get closer. With all of this advice I think I will be able to do just that before too long.
ObliO,
Thanks for telling me how I did what I did!! That is one of the biggest hurdles that I face....understanding the math and science behind the photography. Usually I can see a good shot, but it is the scientific application that holds me back.
L
__________________

 

[flowerfacade]

0bli0,
You recommended that I get a teleconverter, which magnifies the focal length of the lens (generally by 1.4x or 2x). so a 50mm 1.8 would become a 70mm (~2.8 max aperture). this will help you get a tighter image from further away. What brand/kind do you recommend that I use? And anything else I might need to know in my search.
L

 

[0bli0]

personally, i'd recommend either the Tamron SP or the Kenko pro 1.4x (they're actually the same product). they work with almost all lenses (unlike the Canon and Sigma versions). the SP/pro models have much better optics for not much more money. you can also use the standard versions (non-SP/non-pro/teleplus). i don't recommend the 2x version of any of them as they're optically not very good and also you're losing 2 stops of light, so you lose the nice bokeh and also the ability to take deent pictures without a flash indoors.