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Olympus C7x0 and teleconverters

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Old Friday 23rd January 2004, 12:40   #26
RAH
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Thanks very much normjackson! Your advice is a big help. I try to take pictures of birds, but they are so damn small! The converter might help get me close enough. :-)
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Old Saturday 24th January 2004, 02:08   #27
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Know what yer mean RAH; too small, too timid and that's just the camera zoom. Looking in BirdForum gallery, see Gaukur seems to have got things sussed with the C2100 with 1.7x. And only t'other day was thinking these look pretty good for C2100 with help of only 1.45x convertor :
http://www.pbase.com/bdjh/nature_pics

Of course the C730 doesn't have the image stabilisation of the C2100 but, if you haven't done so, do check out Leslie's pictures in the gallery with C700 series cameras plus B300 convertor.
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Old Saturday 24th January 2004, 21:28   #28
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Thanks for the info! Those pictures are really nice! Gaukur, thanks for letting me know about your C2100. Sounds like exactly the situation I have with the C-730 (supposedly not working with extender). I just ordered a TCON-17 yesterday. As soon as I get it I'll check it out and post my impressions here. Hopefully, I'll be able to confirm that it does indeed work fine with the C-730 too...
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Old Wednesday 28th January 2004, 19:34   #29
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I received my TCON-17 teleconverter today and have tried it out on my C-730 camera. As hoped (and predicted on this forum), it works great! I sure am glad I did some internet searching on the topic and found this forum! Thanks for all the good advice! Only trouble now is that I no longer have lack of magnification as an excuse for lousy bird pictures. Well, I'll just have to come up with a new one... :-)
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Old Monday 9th February 2004, 10:25   #30
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Good luck with your TCON-17, I have been using one for a couple of months now and am very pleased with it. You can see my pictures at
http://members.optusnet.com.au/ozbirds

For stability, and to save lugging a tripod around, I have now got a monopod. I keep it in the unextended position at about 90 deg to the camera, and tuck it in my armpit. I am then able to steady the camera and lens, yet have full mobility when out bird photographing.

Mike.
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Old Thursday 4th March 2004, 16:40   #31
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Only recently I found this thread and I am glad I did since I saw IanF message regarding his experimenting with the Eagle Eye5x zoom which dissuaded me from trying it (his experience plus the EE5's high price here in the USA).

I would like to point out that there is an adapter similar to the CLA-4 but with a 52mm front thread. This allows other tele-converters to be used without step rings or with smaller step rings (the front thread on the CLA-4 is 55mm).
I have seen these adapters available (in the US) at scopetronix.com and at photofilter.com.

Such an adapter makes it easy to use Canon's 2.4x teleconverter (Canon TC-DC52, rear thread 52mm, front lens diameter 66 mm) on the C7x0s. This 52mm adapter would also simplify coupling a Kenko3x (KUT-300, 37mm rear thread, 68mm front lens) teleconverter since the Kenko comes with an adapter ring for a 52mm thread.

I have not tried any of those two other converters but I just got the Kenko and as soon as I try it out I will show test photos in BF. This other converters sell for about the same price as the TCON1.7. Incidentally I have the TCON1.7 and agree with everybody that it is a great lens for the Olys.


Dalcio
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Old Monday 8th March 2004, 17:07   #32
mipettin
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dacol

I am in the market for a teleconverter for my Oly 740. I'd really like something meatier than 1.7 - would really like to see some sample pics with the Kenko. The optics of the TCON17 are meant to be great but I'd trade off a little in optics to get closer. For my Oly with an equivalent f of 350mm, x3 would give me 1050mm - woo hoo. Might need lots of bright light to get decent pictures though :-)

Martin
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Old Monday 8th March 2004, 17:29   #33
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Hi Martin,

Be very careful about wanting a more powerful converter. It's not quite that straight forward. A converter not just magnifies the subject, it also magnifies any defects in the lens. The more powerful a converter you use the more soft the images become.

One advantage of the Tcon17 / B300 is that no noticeable light is lost entering the lens, in fact the light gathering properties seem to be increased. It's a very wide lens gathering plenty of light which aids higher shutter speeds and narrower apertures ie. more depth of field.

A 5x converter is often very long and very narrow losing you at least 2x f-stops in addition to degradation of images. You could get reasonable results with a 3x optical zoom camera (I had an Olympus C2000Z) and a 4x one (CP4500), but stability was a big issue and focus another and it was still hard to get a keepable birding shot. It was certainly no use with the Olympus C2100UZ which has a 10x optical zoom due to excessive vignetting and very soft images indeed.

Last edited by IanF : Monday 8th March 2004 at 17:32.
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Old Tuesday 9th March 2004, 02:32   #34
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Quote:
Originally Posted by mipettin
dacol

I am in the market for a teleconverter for my Oly 740. I'd really like something meatier than 1.7 - would really like to see some sample pics with the Kenko. The optics of the TCON17 are meant to be great but I'd trade off a little in optics to get closer. For my Oly with an equivalent f of 350mm, x3 would give me 1050mm - woo hoo. Might need lots of bright light to get decent pictures though :-)

Martin
Well, I managed to do a bit of testing with the Kenko 3x this weekend. Just took a handful of photos. I took pictures of a life size model of a Green-winged Teal (size: 14 inches) at a distance of 50 ft. The results are attached. The pictures with the Kenko were soft, ie, not sharply focused. I took also a picture of a Mourning Dove at about 30 ft. The test pictures were either reduced in size or cropped but not further processed. The dove picture was treated with Photoshop.

Dalcio

Here are the pictures:
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Old Tuesday 9th March 2004, 09:28   #35
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Thanks for the images, the Kenko images are very soft as you say. Was the camera on a tripod? What's your view on the two lens?
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Old Tuesday 9th March 2004, 14:08   #36
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Quote:
Originally Posted by mipettin
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Thanks for the images, the Kenko images are very soft as you say. Was the camera on a tripod? What's your view on the two lens?
-
The camera was on a tripod on solid surface. I shot using the remote controller of the c-750. There was no wind. Admittedly the light conditions were less than ideal due to the time of the day and the geometry of my backyard (the sun light was coming from a direction perpendicular to the line of sight from the camera to the object). I would halp press the shooting button to get an initial focus and then take the shot using the remote. I used the "spot" focus option in the camera with the selected focus area being the centre of the frame. In aiming I put the head of the decoy in the focus area.

It is possible that the focus problem has to do with using a step-ring (the Kenko has a 37mm thread and I had a 52mm adapter on the camera and thus had to use a 37-to-52 step-up ring) which could have impaired the mating of the two optical systems. However notice the amount of chromatic aberration (CA) in the Kenko photos. In fact the softness of the original plus the CA caused an artfact in the enlarged pictures: the mooring ring under the decoy appears in a different orientation in the enlarged Kenko pictures. This has to do with the Photoshop interpolation algorithm dealing with the thick CA halo in the original picture. I am going to try another test using a different coupling arrangement. If it doesn't improve the focusing I may return the lens. Also the Kenko seems to have a very narrow area in the center where it focus better with degradation towards the edges.

The performance of the TCON 1.7 was excellent , except for the larger pciture it is almost if there where no extra lens between the object and the camera lens!

Dalcio
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Old Tuesday 9th March 2004, 16:14   #37
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I'm sure I've read the same conclusion on a different camere site - another wildlife photography site but I cannot remember which. I.e. the Kenko produces very soft images whereas the TCON 17 is very good indeed.

One thing I still haven't got my head round is focusing with the TCON-17 - does the auto focus still work or do you need to use manual focus. For you test you could use the focus lock on the Oly.

In the set up you can set the button marked AEL to focus lock rather than the default which is exposure lock. I think it would be worth repeating your test in more favourable lighting conditions.

The alternative is to use the timer option on the camera press the little clock button to turn it on - it is left of the AEL button and then focus lock and press the button - 12 seconds later it will take the pic.

PS - Sorry if you already know the stuff about focus lock and timer buttons above. It is just that I didn't read my manual properly until recently - benefit of a camera class I attend - these Oly's have a lot underneath the hood!
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Old Tuesday 9th March 2004, 16:54   #38
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The camera autofocus works just fine through the Tcon17.

To be fair the EagleEye does have a reputation of being fairly good optically, certainly better than some of the opposition. I don't recall the CA ever being as noticeable as on the Kenko. Sharper photos can be obtained too, but steadiness is an issue. With mine I had the EE tripod mount bracket, but it's a fiddly set up to use as the lens needs to be half focused and then the camera can utilize it's autofocus.
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Old Monday 15th March 2004, 16:17   #39
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Quote:
Originally Posted by mipettin
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PS - Sorry if you already know the stuff about focus lock and timer buttons above. It is just that I didn't read my manual properly until recently - benefit of a camera class I attend - these Oly's have a lot underneath the hood!
-
I actually did not know this (the uses of the AEL button), thanks for the information. Like many people I use the manual on a strictly "need to know basis", which is not very wise...

I ended up returning the Kenko for a refund. Besides the CA another problem was the very narrow diameter of the focus area in the center of the lens. This is part of the problem in the test pictures that I posted. I had put the decoy's head in the "focusing spot" of the Oly's screen and with the TCON most of the body of the decoy was in fairly good focus while with the Kenko it degenerated very fast towards the tail. Another reason was that with the better quality of the TCON's pictures I could do some heavy cropping and still have at least a Web quality picture, this was not the case with the Kenko.

I must also correct something I said in the previous post: I atributed a change of appearance of the ring under the decoy to a possible distortion in resizing due to the strong CA in the original. Now I think that the shape has to do with the different perspective in each of the 3 different pictures due to the different magnifcation in the originals.

Take a look at this site for experiments with yet another lens for the Oly-C-750: http://www.timotk.net/crystalvuetest2.htm

Finally, as IanF said in his post, the TCON does not interfere with the autofocus, it is only mechanically attached to the body of the C-750, it is not even attached to the camera's lens assembly. It works using the same principles as those used in digiscoping, only using a 1.7x spotting scope.


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