DOI HQ7 conversion (1 Viewer)

Here is my first attempt at converting a DOI HQ7 2x TC.

The lens cell is superglued into a bayonet end ext tube for Nikon AF, The bayonet also has the EMF chip glued on - later I can programme it for the focal length and equivelant F Stop. Note also the doi came with a neat little hard case, just perfect size for the mod.

An image taken in test, subject about 15 mtrs.

Compared to the kenko 2X TC, I calculate the DOI mod is 2.2X and a little faster at equivelant ISOs

Nice one there. That glue at the back of TC, can you get it painted flat black. It look highly reflective. Can you run some test as I mentioned in the other thread, compare the results of the bird taken with and without the DOI TC. Any specific advantages of the DOI over the others?

alphan said:

Nice one there. That glue at the back of TC, can you get it painted flat black. It look highly reflective. Can you run some test as I mentioned in the other thread, compare the results of the bird taken with and without the DOI TC. Any specific advantages of the DOI over the others?

Click to expand...

When I had a Pentax dslr I tried in the region of 10 - 15 various 7 element teleconverters. The Pentax mount probably has the most 7 element converters available of any camera mount. All of them apart from the DOI would become soft at around 30m or less. The DOI HQ7 was the only one I found that would give sharp images at any range. Only ones I didn't try was the Kenko Pro 2X and the big brand names like Canon, Nikon etc due to the costs.

Now though I'd recommend just taking the elements from a zoom lens.

At 30m or more the teleconverter/barlow/telenegative will resolve way more detail than just the 600mm scope cropped. I took a few images this morning that I'll try and get up later today.

Paul.