Originally Posted by Overfocused I don't think a 50 with tubes is still 50 :) The DOF diminishes the most with distance and second with the F rating. I'd personally never shoot a macro at F1.4 unless I was desperate since you would barely get any detail out of it.

Oooh, I'm saying 50 f/1.4 just to designate that as a specific non-macro lens for the example. Not to use the lens at f/1.4. Sorry to be confusing on that!

What is a 50 w/ tubes then? I'm digging around on the web for how to calculate the adjusted FL, but am not finding the answer.

ETA: actually I'm reading that additional tubes don't change the FL of the lens?

Originally Posted by BeardedChick ETA: actually I'm reading that additional tubes don't change the FL of the lens?

what it change then ???

ofcourse FL is changed
by the length of the tube , ea , 50 + 12 = 62

Originally Posted by BeardedChick Oooh, I'm saying 50 f/1.4 just to designate that as a specific non-macro lens for the example. Not to use the lens at f/1.4. Sorry to be confusing on that! What is a 50 w/ tubes then? I'm digging around on the web for how to calculate the adjusted FL, but am not finding the answer. ETA: actually I'm reading that additional tubes don't change the FL of the lens?

It shifts the minimum capable focus distance of the lens. So lets say you add a 20mm tube, I believe it'd be the effect of having a 70mm with focusing at whatever distance range it changes to

Originally Posted by Overfocused It shifts the minimum capable focus distance of the lens. So lets say you add a 20mm tube, I believe it'd be the effect of having a 70mm with focusing at whatever distance range it changes to

Cool, that's an easy one to try then. I'll set my zoom lens to 80mm and add a 20mm tube, and it should be the same angle of view as the 100 macro w/ no tubes, right?

Originally Posted by BeardedChick Cool, that's an easy one to try then. I'll set my zoom lens to 80mm and add a 20mm tube, and it should be the same angle of view as the 100 macro w/ no tubes, right?

It should be. I know the focal length will = 100mm but I have no idea what the magnification factor will actually be. Plus, you can't focus to infinite.

Hello! I have a few more questions about extension tubes. I have a Canon 100mm 2.8 Macro and I too find that I still want much closer. I read the info above but am still somewhat confused about some things. Can you use extension tubes on macro lenses or are they made for other lenses to make them more like a macro? Why is there such a difference in price if they are just tubes that go between the body and lens? I looked at Kenkos which were close to $200 dollars but also saw a same set by a different company for $60. Sorry if these are dumb questions, but I am really just not clear on this and I don't want to shell out money for something I can't use!

Originally Posted by clickin girl Hello! I have a few more questions about extension tubes. I have a Canon 100mm 2.8 Macro and I too find that I still want much closer. I read the info above but am still somewhat confused about some things. Can you use extension tubes on macro lenses or are they made for other lenses to make them more like a macro? Why is there such a difference in price if they are just tubes that go between the body and lens? I looked at Kenkos which were close to $200 dollars but also saw a same set by a different company for $60. Sorry if these are dumb questions, but I am really just not clear on this and I don't want to shell out money for something I can't use!

You can use extension tubes to get closer with just about any lens including a macro lens. With your 100mm macro lens you will be able to get to 2:1 magnification with a set of ext tubes (68mm).
The cheapest extension tubes do not have any electrical contacts so you lose control of the lens aperture which makes it fairly hard to use them. There is still a bit of a price range between the ones that have electrical contacts, Kenko is just a readily available good quality brand, but you can find other brands which vary in their quality. I actually use some other brand ext tubes and have had no problems with them.

Brian v.

Thanks for the info Brian! Very helpful!

Hey you guys im new here and new at macro
resently i got from a friend 100mm macro len without IS (the old model)
and i had fun using but felt i wanted to get more closer so i got those cheap ext tubes on ebay (without electrical contacts) i read here a few guides that is very helpful! so thank you all
but i still have some questions and in need for tips and feedback

1. Is photostacking work only if u shot from the same place? same dof? (with tripod too?)
2. I been thinking to get a external flash for my 550d, which one should i get? just not too high price
3. I love to shoot bug and less flowers and all but for some reason alot tell me to shoot flowers first but i found taking shoot of a flower is just boring, is it absolute necessary for macro beginners ?
4. Is there a way to change aperture with the extension tubes? cause i find it very hard to get focus with low aperture at all frame
5. I been think to get tripod with focusing rail , is it useful to shoot moving objects ? or just flowers? if so which should i get?
6. I will be very grateful if anyway of u would give me more tips and feedback on my gallery

this is my gallery
http://500px.com/Daniel819
Thank you!

@ Danielp ,
-you need tubes with contacts
-for bugs , the use of a tripod is not handy , try to practice handheld

read the tutorials first , then start asking
http://www.dgrin.com/showthread.php?t=143373
me and a lot of others here are glad to help then

I have read everything on that guides and tutorials
and i have more questions haha but for the time being i will be very glad if someone could answer me the ones on my last post
and thanks basflit!