This thread may get geeky.
A while ago I had a batch of aspheric lenses made and about 950 have been sold so far, (all through CPF). For those who don't know what I'm talking about, a search for 'ahorton aspheric' will give most of the relevant threads.
Saabluster, (known for creating the DEFT family of high-end throwers) recently brought to my attention his concerns and disappointment at the variation in the 200 lenses he bought.
Rather than repeat what he told me, I've invited him to show his findings here so that anyone who considers buying my lenses has the full story. After that, I expect that others who have bought my lenses can share their experiences (good or bad) and a consensus can be reached about whether or not there is a problem.
My own position is this:
- I'm aware of some variation since I use a fairly cheap method of moulding to produce these lenses in small quantities.
- For my own lights I have never cherry-picked the best lenses because the variation didn't bother me enough in my applications. Obviously I weed out any with chips or scratches but that's all I do.
- I've used a lot of lenses and some do focus better than others, but I never had one bad enough that I wanted to swap it. Of course we know Saabluster to only ever use the very best in everything.
- I tested 20 lenses last night when I got the email from Saabluster, but I couldn't see any significant variation. Of course I'm open to learning and doing more thorough tests.
I want this thread to stay fairly technical and become a useful resource on testing lenses but here are some possible future actions (more ideas will be welcome when we have enough information) if the variation is declared to be a problem:
- I sort the lenses into bins. The best ones will be more expensive. The average price will also go up because the job sounds really boring and this is meant to be a fun hobby.
- I continue selling unsorted lenses and everyone acknowledges that there's a bit of variation and risk.
- I sort some into bins and others get left unsorted. So buyers can choose either to take a risk or buy the best and the prices will be appropriate.