Size matters - C mount Teleconverter

[saffersteve]

Wow all work and no play....I haven't posted for months.

Anyhow just wanted to get some thoughts / experance on C-mount Teleconverter (TV Extenders) of which there is suprisingly little info.

I've played with a few C mounts and like there Low light and weird bokeh but as I am using a APS-C I am always on a losing battle with vignetting.

So my thinking is......is it possable to increase the Image circle using a teleconverter?

Now I'm well aware that Teleconverters have a number of effects including loss of light and increasing the optical abrasions...but

is this not better than using digital zoom and smaller portions of sensors?

Another factor I've considered is that the lenses were designed for 1Meg to 5Megapixel resolution...so I'm not expecting magic just hope to get a little more use out of what I've got.

Ok so my assumpions is based on the teleconverter increasing the image circle and covering more of the sensor....which I'm yet to get a definitive yes or no ...and this could be the shortest thread if this is not the case.

I have a 1.5x converter (1 stop) arriving in the next few days and will post findings and really hope the 11.5mm-90mm F2 becomes a usable 17.25mm - 135mm F3 Parfocal lens for HD video.

Please let me know your thought / experance.

[Nordentro]

I have 2 teleconvertors from canon. 1.5 and 2. The good part is that they are opticaly very good with little loss of sharpness. The bad part is that they wont fit my 25mm lenses because of protrubing elements and the vignetting is the same or slightly more

[saffersteve]

hmmm...I can see how if the entire lens cluster shifts and protudes to far back this would cause a problem. Hopefully the 1.5 I'm getting doesn't bump the lens I have.

Little concerned about the last part "vignetting is the same or slightly more".....

As a test i've played with my PK and M42 Tc's and they seem to produce a larger Image circle ...so fingers crossed.....

[Nordentro]

Ok, looking for your review when it shows up