Horseman 2x teleconverter

Has anyone tried this converter? Does it significantly degrade image quality?

Guy

Hello Guy,

I've tried the converter on a 150/5.6 sironar lens and found that the resolution drops by more than 50% (from 300 lines/mm to 120 lines/mm) and the contrast was slightly reduced in the overall image. Now the fact that the resolution drops by 2x is understandable, since all the converter does is smear out the image over a larger surface. The drop in contrast has to do with the lens quality of the converter and with the coating and the extra number of glass surfaces. All in all it is not a bad solution to have a very economic and light extra focal length in your bag, but never ever look at the results of a real 300 mm (like the Nikkor 300/9 M lens) side by side on the lighttable. But then that is more money and (only sightly) heavier. As a last remark, the effective aperture goes from 5.6 to f 11, so the combination of the teleconverter and sironar is not very sensitive (a Nikkor 300 is f9)

Bert

If the goal is to have a lightweight combination of two focal lengths, I suspect an older Schneider Symmar convertible might be just as good and would be even more compact and lightweight.

I did own one of this converters which I believe it was the only one ever sold in Italy, years later I showed it to the Duch importer who had never seen one, it is currently living in a window display of a reputable second hand camera shop where is going to stay a long time before somebody will buy it for no good reason other than the price, which will have to be very low. Infact with his low performance, high cost (if new )and 2 stops aperture loss and limited image circle, I'd rather buy a cheap process lens with a shutter (apo ronar 300mm for example) and I'll be sure of a much higher quality. Mind you it isn't a bad solution for traveling light, not much worse in quality than convertible lenses, but, frankly speaking , give me a few ounces more of weight and a little more money and I'll get you a better lens. Good Luck anyway!

I've got one of these sitting on my worktable right now to try out but have not yet had a chance. One advantage it has over a standard 300 mm is that it requires no more bellows draw than a 150 mm so if you are bellows limited it might be attractive. I can answer to the weight in a very unscientific fashion....sittimg right next to it is my 300 mm Fujinon A and the 300 is only marginally heavier. BTW, regardless of the performance of the 150 I am certainly not gonna give up the 300A.

Ted

I believe that teleconvertors usually work better on long lenses.

Has anybody tried using one on a long lens (300, 600, 900mm)

There is presumably a limit on the diameter of the rear element of the prime lens - and a what effect on the image circle.

On a fixed format convertor, you get a magnified version of the middle half of the image, but Does the LF convertor simply double the image circle and image angle?

This gives no more subject angle for movements, but would it enable you to use 5 x 4 ( e.g. Nikon) lenses on 10 x 8?

if you buy this thinking that the flange distance will be dramatically affected you'll be wrong, I can't remember the exact figures but there was a minimum gain compared to a 300 mm, of course if you are very limited by your bellows or otherwise the construction of the camera every little bit counts! The lens can oly be used on 150mm, That's what hoseman says (if it would be otherwise they would say it wouldn't they?)on its accompanying leaflet. Image circle stays more or less the one of the 150mm.

Thanks folks!
I was actually thinking about it as an alternative lightweight solution but it doesn't sound like I'll be happy with image quality.
Ted - I believe it does require 300mm (or close to it) of bellows to focus so there's really not much saving there.
I decided to go with a roll film back for images that need a tighter crop. This way I can use my existing lenses and less expensive film (I'd rather have a sharp 6x7 than a fuzzy 4x5).

Guy
Scenic Wild