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Old 21-09-2013, 06:06 AM
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nebulosity. (Jo)
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Join Date: Jul 2013
Location: Cecil Plains QLD
Posts: 1,228
A New Lens For Wide Fields

G’day everyone,

I’ve been thinking and have decided that as my home built mount is not able to have autoguiding, and I hate manual guiding, I’m going to stick to doing wide field stuff until I get around to building a new mount.

Now, currently I’ve been using a Panasonic GX1 and a Nikon 85mm lens, which, as the GX1 has a 17x13mm sensor, has given me a nice 170mm focal length.

The GX1 is a nice little camera and has given me some great results but is limited by the fact that it can only do 128 second exposures so recently I’ve been working on cooling a Canon 350d to use as my wide field camera.

But I got a bit of a problem with the 350d, as it has a larger sensor than the GX1, with the 85mm lens I’m only going to be getting a 136mm focal length, and added to the fact that it’s only 8mp vs 16 mp for the GX1 I don’t think 136mm is going to give me the resolution I’m looking for, what do you reckon?

So, I’m looking for a lens around 100 to 200mm and the only criteria is that it has to be super sharp at f4, have minimal CA, and have a second hand price of under $500.

Any ideas?

The 85mm lens would probably work nice but I was hoping to get a bit more close and personal, I reckon the max unguided exposures I could get on my mount at 200mm would be around 5 to 8 minuets, it that good enough?

If you know of a cracker lens thats over my budget you might as well mention it as well, I like to goggle.

Thanks a lot.

Cheers
Jo

PS Nikon lenses are not out of the question as I have a Nikon to Canon adapter.
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