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mtngal · Nov 20, 2007, 1:59 PM

I have a 100mm macro lens that does 1:1. My situation is that I want to increase the size sometimes (increase magnification), but don't want to get any closer than the normal macro lens focus distance (reason for not using an extension tube or a dioper lens, which both allow you to get larger by getting closer, which I don't want to do). I was thinking of getting a rear element teleconverter, but wondered if it would change the minimum focus distance in some way. Do they? The only one I played with was lousy and I only played with it for it's long distance capability, never for macro.

Thanks for any information.

TCav · Nov 20, 2007, 9:18 PM

I just tried it with my KM5D, Minolta 70-210mm f/4 Macro ('Beercan') and a Quantaray 2X DG TC. As far as I could tell, the minimum focus distance was about the same, with or without the TC.

mtngal · Nov 20, 2007, 10:13 PM

Thanks for the information - looks like I'll start looking for something along the lines of a 1.7 TC. Get it for the macro application but play with it for birding? Not such a bad idea at that.

TCav · Nov 20, 2007, 10:16 PM

Didn't you once mention that you had a TC that you took the optics out of so you could use it as an extention tube?

In addition to doubling the focal length, my Quantaray 2X TC adds gobs of CA. Keep that in mind when you go shopping.

mtngal · Nov 21, 2007, 8:03 AM

Yes - the TC I had was a very poor one (had originally been bought by my father sometime in the 1980's I think). I played around a bit with it when I got my first dSLR but the image degradation (softness mostly) was so bad I gave up trying to use it. When I decided it was useless as a TC, I tried to remove the screws holding the optics, but couldn't break them loose. Since I wasn't keeping the glass anyway, I took a chisel to it - instant extension tube. More useful but not quite what I want for a couple of things, hence the thought about getting a better TC.

TCav · Nov 22, 2007, 6:57 AM

mtngal wrote:

Quote:

Since I wasn't keeping the glass anyway, I took a chisel to it - instant extension tube.

A CHISEL!!!

I wish I could have seen that! :-)

mtngal · Nov 26, 2007, 10:31 AM

It gave me a respect for just how hard lens glass really is - it was harder to break than I had thought, and in the end I managed to get the metal framework holding the glass elements out. It never had electronic contacts, but it does have the lever so the camera can stop down the lens. As long as the lens has some type of aperture ring it will work as a manual lens (my first attempts at macro were with this anda 50mm 1.7 manual lens).

Calicajun · Nov 26, 2007, 8:08 PM

TCav wrote:

Quote:

mtngal wrote:

Quote:

Since I wasn't keeping the glass anyway, I took a chisel to it - instant extension tube.

A CHISEL!!!

I wish I could have seen that! :-)

I agree that would have been fun to see.

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Nov 20, 2007, 1:59 PM	#1
mtngal Senior Member Join Date: Nov 2005 Location: Frazier Park, CA Posts: 16,177	I have a 100mm macro lens that does 1:1. My situation is that I want to increase the size sometimes (increase magnification), but don't want to get any closer than the normal macro lens focus distance (reason for not using an extension tube or a dioper lens, which both allow you to get larger by getting closer, which I don't want to do). I was thinking of getting a rear element teleconverter, but wondered if it would change the minimum focus distance in some way. Do they? The only one I played with was lousy and I only played with it for it's long distance capability, never for macro. Thanks for any information.

Nov 20, 2007, 9:18 PM	#2
TCav Senior Member Join Date: Sep 2005 Location: Washington, DC, Metro Area, Maryland Posts: 13,826	I just tried it with my KM5D, Minolta 70-210mm f/4 Macro ('Beercan') and a Quantaray 2X DG TC. As far as I could tell, the minimum focus distance was about the same, with or without the TC.

Nov 20, 2007, 10:13 PM	#3
mtngal Senior Member Join Date: Nov 2005 Location: Frazier Park, CA Posts: 16,177	Thanks for the information - looks like I'll start looking for something along the lines of a 1.7 TC. Get it for the macro application but play with it for birding? Not such a bad idea at that.

Nov 20, 2007, 10:16 PM	#4
TCav Senior Member Join Date: Sep 2005 Location: Washington, DC, Metro Area, Maryland Posts: 13,826	Didn't you once mention that you had a TC that you took the optics out of so you could use it as an extention tube? In addition to doubling the focal length, my Quantaray 2X TC adds gobs of CA. Keep that in mind when you go shopping.

Nov 21, 2007, 8:03 AM	#5
mtngal Senior Member Join Date: Nov 2005 Location: Frazier Park, CA Posts: 16,177	Yes - the TC I had was a very poor one (had originally been bought by my father sometime in the 1980's I think). I played around a bit with it when I got my first dSLR but the image degradation (softness mostly) was so bad I gave up trying to use it. When I decided it was useless as a TC, I tried to remove the screws holding the optics, but couldn't break them loose. Since I wasn't keeping the glass anyway, I took a chisel to it - instant extension tube. More useful but not quite what I want for a couple of things, hence the thought about getting a better TC.

Nov 26, 2007, 10:31 AM	#7
mtngal Senior Member Join Date: Nov 2005 Location: Frazier Park, CA Posts: 16,177	It gave me a respect for just how hard lens glass really is - it was harder to break than I had thought, and in the end I managed to get the metal framework holding the glass elements out. It never had electronic contacts, but it does have the lever so the camera can stop down the lens. As long as the lens has some type of aperture ring it will work as a manual lens (my first attempts at macro were with this anda 50mm 1.7 manual lens).