I thought I'd share my initial experiences of Altair's Lightwave 0.8 reducer which is billed as having field flattening properties, I thought I'd put this to the test:)
After switching back to an ED80 I was in the market for a reducer flattener to try and bring the f/ratio down a bit from f/7.5 which is a tad bit on the slow side. I looked at the usual suspects SW 0.85 and the TRF-2008 but to be honest I was running out of things to sell to fund one:D Then Nadeem (Deneb) mentioned the lightwave 0.8 reducer which was less than half the cost of the next cheapest option. I Googled about and couldn't find much info on these so I decided to take a gamble and buy it and review it. I wasn't expecting much to be honest and any improvement in the corners I would see as a bonus.
I got back from work the other night and it was crystal clear for a change so I went straight out to the obsy and setup on M81/82 as it was well positioned and I don't have a modded camera at the moment so nebulae were out.
I ran off 34 x120 seconds subs (unguided I'm rustic) plus darks and flats with my Canon 400D @ ISO 800, and stacked them in DSS, and tweaked about in PaintShop Pro.
The reducer itself has a lovely piano black finish and feels solid and well made for the price bracket. The glass elements didn't seem to show much in the way of coatings but they where clean and blemish free. The 2" nose piece is push fit onto the scope and there is a thread at the back for T-ring attachment. My spacing was simply the 10mm T-ring plus distance to the DSLR chip, so as simple as it gets.
When used with my ED80 focal length 600mm and f/7.5 it brings it down to FL480 @ f/6 which is fast enough.
Below is an uncropped jpeg of the full FOV plus individual closeups of all four corners, top left, top right, bottom left, and bottom right.
Bearing in mind I didn't have my polar allignment spot on so there is a touch of eggy stars even in the centre of the image due to drift, I must say I'm very impressed with the stars in all four corners of the image they look close to round and not disimilar to the stars in the centre. Thus the field looks flat to me and perfectly acceptable. I would be quite happy using the full FOV with very little cropping indeed. This reducer has exceeded my expectations and I'm very pleased I purchased it. Having said this I'm the first to admit I don't have the best eye for detail so all coments and opinions are welcome:)