I keep doing test with tube lenses; today I tested the Raynox DCR-250 8 diopters 125mm FL
First I have taken pictures with the Raynox focused to infinity, in normal and reversed position
In normal position quallity at infinity is rubbish but even across the frame, in reversed position it is good (ish) in the center and has strong spherical aberration in the corners with more CAs
Normal
http://farm9.staticflickr.com/8450/7999 ... de17_o.jpg
Reversed
http://farm9.staticflickr.com/8447/7999 ... e5be_o.jpg
Crops

Full size crops
http://farm9.staticflickr.com/8172/7999 ... d780_o.jpg
By looking at this pictures we would say that the raynox is not going to work well on normal position because of the very bad quality in the center of the frame
Then I took a couple of pictures with Nikon CFI 10/0.25 to see it, magnification at infinity around 6.2X. They have no sharpening
Normal position
http://farm9.staticflickr.com/8177/7999 ... a750_o.jpg
Reversed position
http://farm9.staticflickr.com/8441/7999 ... 26f1_o.jpg
Crops

Full size crops
http://farm9.staticflickr.com/8030/7999 ... dfbf_o.jpg
You can get better looking details with some sharpening
Full size crops with some sharpening
http://farm9.staticflickr.com/8041/7999 ... d722_o.jpg
It is clear to me than the Raynox works better in normal position, with very good corners at 6.2X on APS-C with the Nikon CFI 10/0.25
EDIT This is how the Raynox looks adapted to normal and reversed position, description few posts bellow

Also with Raynox DCR-150; 208mm FL
Normal
http://farm9.staticflickr.com/8304/8006 ... 25f0_k.jpg
Reversed
http://farm9.staticflickr.com/8303/8006 ... 0ac8_k.jpg
Crops

Full size crops
http://farm9.staticflickr.com/8031/8006 ... 8bb1_o.jpg
DCR-150 and mitutoyo 5/0.14 on NEX-5N
Normal position
http://farm9.staticflickr.com/8459/8006 ... b89d_o.jpg
Reversed position
http://farm9.staticflickr.com/8176/8006 ... 9e42_o.jpg
Crops

Full size crops
http://farm9.staticflickr.com/8040/8006 ... e7a6_o.jpg
And with Raynox 6X from CM-3500 kit; 170mm FL
Normal
http://farm9.staticflickr.com/8176/8006 ... beb3_k.jpg
Reversed
http://farm9.staticflickr.com/8448/8006 ... d91_k.jpgg
Crops

Full size crops
http://farm9.staticflickr.com/8306/8006 ... 732f_o.jpg
Raynox 6X and mitutoyo 5/0.14 on NEX-5N
Normal position
http://farm9.staticflickr.com/8035/8006 ... 3117_o.jpg
Reversed position
http://farm9.staticflickr.com/8176/8006 ... 78c7_o.jpg
Crops

Full size crops
http://farm9.staticflickr.com/8305/8006 ... f113_o.jpg
Regards
Javier