Picked up a Unicorn lens - complete with test shot

[D.Gray]

So I was browsing KEH.com for Pentax mount lenses and found a Sigma 500mm 1:4.5 in the Pentax mount. Sigma discontinued this lens at least five years ago in the Pentax mount.

So I put it on the Sigma 2x teleconverter I had to see how sharp the image would be, and took two test shots (one at 20 feet, and one at almost 1/4 mile).The 20 foot shot was of Yucca blossoms and the 1/4 mile shot is a Red Tailed Hawk nest on power line girders with chicks about to fledge in the nest.

Here is the Yucca shot:

 

[Saxonbowman]

Wow, looks great!

How does it do without the tele converter? I used to hear that they softened the image, but I suspect the optics are a whole lot better these days.

 

[D.Gray]

Wow, looks great!

How does it do without the tele converter? I used to hear that they softened the image, but I suspect the optics are a whole lot better these days.

They are tack sharp without the teleconverter. I have just found that at times for smaller birds or birds at a distance 500mm wasn't enough lens.

I tried the Teleconverter on my Sigma 50-500mm 1:6.7 lens and it just doesn't work as the image gets so soft it looks out of focus.