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DPChallenge Forums >> Hardware and Software >> Tele converter for Canaon Powershot A40
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 01/23/2004 02:12:19 PM · #1
Hi
I own Powershot A40 and thinking of buying a teleconverter , closeup and wideconverter for my camera . I live in India so i was not able to see teleconverter in person at a shop as in India a40 is obselete.

Has anyone used the Teleconverter as i am bit confused after reading some points mentioned in manual of a40.

First of all i want to know can i use zoom settings as per my wish as i normally do or i have to use it at highest telephoto zoom.
Reason is that i use my camera with studio strobes with help of digital slave and normally end up using from f8-f11 and if i have to use my camera at maximum telephoto setting than i end up with f-14 or f4.8 which are useless for me.

Also how are the other wide convertor and closeup lens
01/23/2004 02:32:19 PM · #2
I used the TC-DC52 2.4x teleconverter on the A40 and it greatly improved on the camera's zoom. It got further and much more clearer than the digital zoom did. I'm not as excited about it now compared to my new camera, but at the time I thought it was amazingly different. You still get the two options when using it fully extended, it depends on the circumstances, but I think I used it at f/11.

As for close-up lenses, I used a set of +1, +2, +4 that I found to be surprisingly good but had to fiddle with distances until I could get a good focus lock.
 01/23/2004 07:38:02 PM · #3
I have the TC-DC52 converter, and you'll definitely have problems with it from f/8 to f/10 (or, in focal length, from 5.4mm to 9.4mm; or in the simplest terms, in the 4 widest zoom steps). At the widest settings, the converter will cause vignetting, which is a round shadow around the outside of the image. It's visible up to f/10 (9.4mm), where its just visible at the corners. Technically, a picture taken at this setting could be usable if you were going to crop it in such a way that the corners were cut off, but I usually avoid that.

Here's effectively what this gives you:

The focal lengths available on the A40 are: 5.4mm, 6.6mm, 7.8mm, 9.4mm, 11.3mm, 13.4mm, and 16.2mm. Since the TC-DC52 is a 2.4x converter, and it's useable at the three longest focal lengths, that gives you the addition of 27.1mm, 32.1mm and 38.9mm. Basically you just loose a couple of steps between 16.2mm and 27.1mm.

I'm not sure I understand what's significant about using f/8-f/11 and why it would be useless for you outside that range. Is it a matter of getting the exposure? Couldn't you compensate by adjusting the shutter speed? Or, if that's an issue, you might be able to compensate with a neutral densit filter and opening the aperature up to the 4.8 range (though that may mess with your DOF - again, I'm not sure exactly what your issue is).

If there are any tests I can shoot for you, let me know. Though I don't have the lighting setup you do, so I don't know how much it would help.
01/24/2004 10:09:44 PM · #4
Hi
First of all thanks a lot for such a great reply. It was really in depth reply.
To start with studio strobes means studio flash and hence it rules out my changing shutter speed in order to compensate aperture.

I work from room based studio with my bed and other furniture lying around. My biggest problem is that I donĂ¢€™t have much space to move my studio flash. I can get maximum of 6-7 metre of distance between my lights and subject, I use jumbo umbrella with my lights,

Since I have a very very small area to move my lights, I am getting proper exposure at settings of f8-f11 in that limited area. If I were choose higher telephoto settings than my aperture goes beyond f-11 thus I start underexposing my shots. One solution is to increase light either by increasing another studio strobe or getting my current lights closer to my subject, both not possible.

If I use wide aperture at settings of f 4-4-8 I tend to grossly over expose my shots to that extent that colours are totally washed out. I cannot move my lights any further inorder to decrease light to my subject. Strobe
So I am stuck with shooting iso 50 at f-8-f11.

I will be highly obliged if you can shoot full-length photographs of a person as I shoot garments on a mannequin. Currently I do crop my photographs but that is because I want size of my subject to bigger
But since there is visible vignetting at focal length of my choice I want to know would I still be able to do cropping with vignetting or not.

I would be obliged if you can shoot full length photographs of a person also some photographs of a subject like a hand watch ( I do product photography) at all focal lengths from 5.5mm-16.2 mm , I hope it is not too much as it will really help me. I do Photography for my own work which I just started and having great time shooting and printing photographs with a40 and if I can use tele converter I would end up delaying need for a new digital camera for a lonnnnng time
Let me know abt neutral density filter, i never knew abt it and how much does it cost, as such i have no issue with dof

Message edited by author 2004-01-24 22:29:37.
 02/03/2004 07:27:47 PM · #5
I shot a series of shots without and with the TC-DC52 on my A40. Anyone interested can view them here. The quality of these shots isn't great because of the lighting, and they were just a quick-and-dirty example. So don't necessarily use these to judge the quality of the lens, but simply as a guide to the affects that the TC-DC52 has on magnification and vignetting. I hope they're useful in helping General, or any other A-series camera owner, in deciding whether this lens works for them.
 02/03/2004 07:44:02 PM · #6
Hey Scott

I hope you didn`t have to keep running up and down the hall :)

Geo
 02/03/2004 08:03:52 PM · #7
Yep, that big ugly giant at the end of the hall is me. That's why my head is cut off on the last shot or two - I had to guess where my head would be when I set it up. That's also why the ladder is there on the second series - I started having trouble focusing on the blank door. (The ladder just happened to be handy.)

So, since I actually did three series (the first time around with the TC I ended up focused on a, um, certain portion of my anatomy), a rough guess would be I walked about 2/10 of a mile to take these. What a workout. :)
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