Pentax Q and EF adapter for use as a SUPER telephoto

[Andy_Hodapp]

With all the talk about the Tamron 150-600mm, I've been looking for a cheaper way to get it super telephoto nature photography. I'm moving to Montana in a matter of months and I will be living close to Yellowstone. I've already gone out and photographed the landscape but I have no real way of getting the animals at a safe distance. I have a 200mm F/2.8 II which is just not long enough. In comes the idea of using a Pentax Q as a teleconverter. I've been looking online at the prices of them and it looks like you can pick them up for about $150 or so and an adapter for $20. I haven't taken the dive and gotten them yet in fear of poor image quality. I can only think that having a 5.6 or a 4.7 times crop factor would bring all of the small imperfections of a lens out. If anyone has tried using a Pentax Q with an adapter I would love to know how well it works. Having a 1120mm F/2.8 sounds pretty awesome to me!

 

[neuroanatomist]

Having a 1120mm F/2.8 sounds pretty awesome to me!

Such a lens would likely weigh over 100 lbs. The 'crop factor' applies to aperture (in terms of DoF for equivalent framing) and ISO noise scales inversely with total light by approximately the same factor. The only thing the smaller sensor buys you is more pixels on target (and that's only because smaller sensors usually have a higher pixel density, but for example the Nikon D800 puts more pixels on target than the Canon T3).

 

[Andy_Hodapp]

Having a 1120mm F/2.8 sounds pretty awesome to me!

Such a lens would likely weigh over 100 lbs. The 'crop factor' applies to aperture (in terms of DoF for equivalent framing) and ISO noise scales inversely with total light by approximately the same factor. The only thing the smaller sensor buys you is more pixels on target (and that's only because smaller sensors usually have a higher pixel density, but for example the Nikon D800 puts more pixels on target than the Canon T3).

I understand that it would not have the equivalent DoF. I was more thinking that it would allow for a faster shutter speed then say something like an SX50.