K
knucklehead
Guest
First off, right to the point -- No, it's not quite free from vignetting
as I had hoped for, but still more than worth doing. Take the two TC's
that give the best quality images, put them together, and you get a
lens that still provides an excellent image. There's only a tiny bit of overall
softening Ron the extra glass, some slight shadowy vignetting with
most apertures, and only the slightest loss of focus in the extreme
corners. I know I'll be getting a lot of use out of this setup...
The two best telephoto lenses that we know of for these cameras are
the Canon tl46 with a 1.4X increase in power, and the B300 with 1.7X.
Both give excellent quality images with no vignetting whatsoever - and a
bit of zoom range thrown in for free (a pretty nice zoom range with the
tl46). With the tl you get a nice 530 mm or so out of your 10X lens, and
the b300 gives an even nicer 646 mm. If you stack these two together
it will give a 2.1X increase -- or right about 900 mm.
So far no one has reported on doing this - probably because it's a bit tricky
to attach them together. It's a bit more trouble to glue up than the other
lenses that have been done, but I think well worth the effort.
The problem is how to get some threads on the front of the tl for the b300
to screw on to. After pestering every camera store I could find for every
sort of adapter ring that might possibly fit, I finally settled on smashing yet
another one of my UV filters for progress. A 55 mm filter ring will fit easily
inside the end of the tl. Actually it will fit way too easy, with a whole bunch of
extra clearance. Now it's a question of how to get the ring positioned properly
and glued solidly without messing up the front element of the tl. Here's what
I came up with -
The ingredients:
http://www.fototime.com/ {EF2F120E-C8F2-43F8-8B3D-1821F0001044} picture.JPG
The wire that is cut into four pieces is a canabilized .040 spark plug gauge.
That's pretty much the clearance for centering the filter ring inside the tl.
The next question is, how far in to place the ring. The closer you can get
the lenses, the less of a problem vignetting will be. I used the small piece
of lens cloth to act as a shim to find the minimum clearance you can get
away with. With the front of the filter flush with the front of the tl, the
cloth seems pretty well compressed between the glass. This might be a bit
on the tight side, but that's how I decided to do it. I'll just need to be extra
careful about any grit when screwing the lenses together (grit shouldn't be
there anyway).
I cut the wire in four pieces to the length of the edge of the front lens of
the tl to the front edge of the housing, and then tacked them on to the
side of the filter ring with a tiny bit of silicone.
http://www.fototime.com/ {C480A224-A908-4F32-9D72-B721CEE65C15} picture.JPG
Now you have a ring that will pretty well center itself in the front of the tl
housing.
The next problem is that there is a pretty large gap between the back of the
filter ring and the front of the tl's lens. This is a bit of a gluing challenge. I
wound up putting a pretty large bead of black silicone around the edge of
the lt's front lens and set the ring into it. This formed a dam for the epoxy
that would be put in the gap between the ring and housing (I'm going to cut
short the details here. If anyone wants more information, just ask)
Glued in place
http://www.fototime.com/ {631689AB-B05B-46F4-99B7-9AE2D34D2CB5} picture.JPG
All together
http://www.fototime.com/ {40F20956-D1A6-404E-8AFC-AB5644B7D763} picture.JPG
I've only had a small chance to test out the final setup.
The weather's turned bad so I'll just post a few examples of what I've got
so far. Please, no art critiques. I'll replace these when I get a chance to take
some more.
All were shot with the e100 at full optical zoom, SHQ, camera softening soft.
No post processing.
The first images of the maps are to serve as a sort of resolution chart, and
give a good look at the absolute degree of vignetting. The first shot is with
just the b300, and the other two are with the combo at f 3.5 and f 8.
The rest of the shots are just to give some idea of how it works in more real
world use. I think all were shot at f 5 or higher.
It's the last album:
http://www.fototime.com/inv/69BCF269C22E1B7
as I had hoped for, but still more than worth doing. Take the two TC's
that give the best quality images, put them together, and you get a
lens that still provides an excellent image. There's only a tiny bit of overall
softening Ron the extra glass, some slight shadowy vignetting with
most apertures, and only the slightest loss of focus in the extreme
corners. I know I'll be getting a lot of use out of this setup...
The two best telephoto lenses that we know of for these cameras are
the Canon tl46 with a 1.4X increase in power, and the B300 with 1.7X.
Both give excellent quality images with no vignetting whatsoever - and a
bit of zoom range thrown in for free (a pretty nice zoom range with the
tl46). With the tl you get a nice 530 mm or so out of your 10X lens, and
the b300 gives an even nicer 646 mm. If you stack these two together
it will give a 2.1X increase -- or right about 900 mm.
So far no one has reported on doing this - probably because it's a bit tricky
to attach them together. It's a bit more trouble to glue up than the other
lenses that have been done, but I think well worth the effort.
The problem is how to get some threads on the front of the tl for the b300
to screw on to. After pestering every camera store I could find for every
sort of adapter ring that might possibly fit, I finally settled on smashing yet
another one of my UV filters for progress. A 55 mm filter ring will fit easily
inside the end of the tl. Actually it will fit way too easy, with a whole bunch of
extra clearance. Now it's a question of how to get the ring positioned properly
and glued solidly without messing up the front element of the tl. Here's what
I came up with -
The ingredients:
http://www.fototime.com/ {EF2F120E-C8F2-43F8-8B3D-1821F0001044} picture.JPG
The wire that is cut into four pieces is a canabilized .040 spark plug gauge.
That's pretty much the clearance for centering the filter ring inside the tl.
The next question is, how far in to place the ring. The closer you can get
the lenses, the less of a problem vignetting will be. I used the small piece
of lens cloth to act as a shim to find the minimum clearance you can get
away with. With the front of the filter flush with the front of the tl, the
cloth seems pretty well compressed between the glass. This might be a bit
on the tight side, but that's how I decided to do it. I'll just need to be extra
careful about any grit when screwing the lenses together (grit shouldn't be
there anyway).
I cut the wire in four pieces to the length of the edge of the front lens of
the tl to the front edge of the housing, and then tacked them on to the
side of the filter ring with a tiny bit of silicone.
http://www.fototime.com/ {C480A224-A908-4F32-9D72-B721CEE65C15} picture.JPG
Now you have a ring that will pretty well center itself in the front of the tl
housing.
The next problem is that there is a pretty large gap between the back of the
filter ring and the front of the tl's lens. This is a bit of a gluing challenge. I
wound up putting a pretty large bead of black silicone around the edge of
the lt's front lens and set the ring into it. This formed a dam for the epoxy
that would be put in the gap between the ring and housing (I'm going to cut
short the details here. If anyone wants more information, just ask)
Glued in place
http://www.fototime.com/ {631689AB-B05B-46F4-99B7-9AE2D34D2CB5} picture.JPG
All together
http://www.fototime.com/ {40F20956-D1A6-404E-8AFC-AB5644B7D763} picture.JPG
I've only had a small chance to test out the final setup.
The weather's turned bad so I'll just post a few examples of what I've got
so far. Please, no art critiques. I'll replace these when I get a chance to take
some more.
All were shot with the e100 at full optical zoom, SHQ, camera softening soft.
No post processing.
The first images of the maps are to serve as a sort of resolution chart, and
give a good look at the absolute degree of vignetting. The first shot is with
just the b300, and the other two are with the combo at f 3.5 and f 8.
The rest of the shots are just to give some idea of how it works in more real
world use. I think all were shot at f 5 or higher.
It's the last album:
http://www.fototime.com/inv/69BCF269C22E1B7
