I'm trying to figure out how teleconverters and extension tubes differ in their results. That is: What changes when I add a teleconverter? and What changes when I add extension tubes? I mostly do macro flora photography.
Thanks.
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I'm trying to figure out how teleconverters and extension tubes differ in their results. That is: What changes when I add a teleconverter? and What changes when I add extension tubes? I mostly do macro flora photography.
Thanks.
Anita, basically a teleconverter will magnify the image by giving you a longer focal length whereas an extension tube reduces the minimum focus distance of a lens thus allowing you to get closer to the subject. I am sure that one of the experts will give you a more detailed explanation.
Just want to say that if you use the in-camera exposure meter to take the exposure readings, then nothing needs to be changed other than the usual +/- compensation that you may want to apply based on the scene you're photographing and how you want your photogaph to look. If you use external exposure meter, if my memory serves me, then your may - especially if you use a few extension tubes stacked together - need to adjust the exposure readings in addition to the just-mentioned to compensate for the light loss due to the increase in the distance between the lens and the film/sensor plan. I think the extension tubes should come with information on that. In these digital days, any minor exposure error could be easily fixed in post-processing though without much ill-effect.Quote:
Originally Posted by Anita Bower
I'm no expert Anita, but just to say that both teleconverters and extension tubes allow you to project a bigger version of the image on your sensor, but they do it in different ways. The teleconverter is a lens which bends the light coming from the lens in front, thus magnifiying the image, and you do all this without having to get any closer to the subject. In contrast an extension tube is just that, a tube, and not a lens, and all it does is give you a closer focusing range. So an extension tube allows you to project a bigger image on your sensor but you do this by getting closer to your subject. And of course you can use a teleconverter and an extension tune stacked together. Another difference is that teleconverters, because they are lenses, have the potential to degrade your image whereas, an extension tube is unlikely to do this. Yet another is that at least Nikon and Canon teleconverters will only fit on some types of lenses, whereas extension tubes fit on all lenses as far as I know. 1.4 teleconverters will cut your light in half but a relatively short extension tube does not affect light levels that much.
For macro work, a teleconverter allows the capture of a larger image of your subject from a greater distance than an extension tube would, all other things being equal. This might be useful for subjects like butterflies or frogs which can be skittish. For macro work on flowers that don't move, an extension tube might be a better option, where the utmost image quality is critical.
Anita the short end on of the explanation is you use an extension tube when you can't focus for being too close !! ... if you need to stay away from your subject but needed bigger in frame then the converter !!
For macro is good to have both, on the Canon side would recommend Canon tubes, they are metal. On the Nikon side the Kenko seem to work better than the Nikon, they AF !! Both come in different sizes 12 or 25 being the most common, would suggest only the 25 and I normally carry three of them.
Hi Anita,
Above advice is all excellent! I use both. While I have a Canon tele.....my older Kenko tubes are metal. Here is another heads up that may affect you.....I have to use my 20mm tube in front of the teleconverter! Not sure if it is the older design of the TC or the 180mm sigma macro....but my TC doesn't fit into the macro unless I also use the 2 in combo. Not really a big deal as when I use that setup.....I am going small game huntung!:D
Hope this adds to the other wonderful info above!
Photo-friends: Thank you so much. I now understand the difference and when I would use each one. Each explanation gave me a bit more and different information. BPN is great for learning!
you carry 3? do you stack them all with one lens? Would it not be easier to just back up? I am just curious as to why? please dont take this the wrong way :D
Hi Allen You can stack several to get closer to the subject. When using my favorite macro lens ... 500 f4.0 IS .. will use all three at times !!
For traditional macro lenses like the 180 it will be useful at times particularly for very small insects like flies, will be able to get close enough for full frame images and more. There is a penalty in loss of light which the camera will figure out but working from a tripod is a must !! ... btw this is why I like the metal rings since they will not bend !
Alfred,
What is the typical "working distance" with your 500 F4 + 3 / 25mm tubes?? Do you get close to a 1:1 with this setup??
Hi David Never figured it out but use it mostly at the Alligator Farm for extreme close up shots and your talking about eyeballs and just a little more :) Not sure it will go all the way down to 1 to 1 !!
btw with the macro lens you do get to 1 to 1 and beyond but for that would be best switching to the Canon MP-65 which will go 5 to 1 !!
Kenko do indeed work very well on the Nikon on do AF :)
... while I think the Nikon don't !!!! :)Quote:
Originally Posted by Lance Peters
So with the Canon extension tubes, you can stack 3 with out fear of the weight of the camera body snapping the lens mounts?
Yes I think so Allen, they have a sturdy build, and are better than the kenko, which are plastic, and will bend.
I bought one and should have it with my 800mm rental. Thanks for all the input!:D
I got my extension tube delivered on Friday (Canon EF25 II) and can not get it to focus using my 300 f/2.8 IS lens. I have tried both my 5D Mark II and 1D Mark IV and it will not focus. I have tried placing it in manual mode and it also will not focus.
I called Canon CPS and they told me that the extension tube wont allow you to track objects like birds, but rather only allow you shorten your minimum focus distance.
My question to forum members is how they use there tubes no pun intended :)
I am extremely frustrated with it and am wondering if its defective?
Thanks.....
Allen- As you probably know the extension tube has pins which connect the lens to the body thus communicating things like aperture and AF drive info. If it's not working in AF then the pins cannot be communicating maybe because the tube is defective or maybe because the plates on the lens, or the pins on the body or plates/pins on the tube are dirty. I would try making sure the pins on the tube move in and out against the springs and that one is not stuck in too far.
I would imagine you could track moving objects so long as they were within the shorter focus range produced by the tube, although I'm not sure why you would want to do that.
I will check and make sure that the pins are clean and functioning but its brand new and I shouldnt have these issues unless its the nature of the lens and I need clarification :)
I want to use it in my back yard where the 300 is a little long and I thought by using the extension tube I would still be able to track....
Allen,
Note that you'll loose "infinity" focus with extension tubes. In other words, beyond a certain distance the AF won't work if you use an extension tube. Not entirely sure what that distance is but my impression is that the larger the extension tube the earlier you loose "infinity" focus.
Perhaps that helps. JR
Move closer to the subject until it comes into focus. These are for close ups and not much else. The minimum and maximum focus distance are both shortened. With my 500mm I can't focus anything beyond about 10-yards.Quote:
Originally Posted by Allen Johnson
and here I thought I had a defective unit. I will definitely give it a try tomorrow.......
Allen, just for info the approximate focussing range with a 25mm tube and the 300/2.8 is 1.65-4 mtrs (5.4 ft to 13 ft) - Anything outside of this range will not focus.
