Re: General comment

Kevin,

Well this really helps. I hadn't considered working distance. Its the same
issue in wildlife photography - probably obvious enough had I given this
some thought. I can get good magnification with the Canon but I need to be
8 inches from the subject, not always possible. If I take off a diopter or
extension, the mag is gone, but I can back up to 8 feet.

I did find an interesting arrangement that I use to photograph butterflies
and other flighty subjects. I stack and intermix teleconverters and
extension tubes behind a 400. I can get back reasonably far but image
quality starts to get sketchy. Ok. Stereo first.


"Kevin Cunningham" <smskjd@xxxxxxxxxxxxxx> wrote in message
news:1C6gf.3383$wf.1564@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> "Nick" <nickmirro@xxxxxxxxxxxxxx> wrote in message
> news:V4WdnciX6IhdTx3eRVn-tg@xxxxxxxxxxxxxx
>> Kevin,
>>
>> Thanks for the help. This is good news. The Wild is being sold by a
>> dealer just 20 minutes away from me. Thanks for this info.
>>
>> Regarding numerical aperture, why do some stereo scopes advertize up to 3
>> and 400x with different objective/eyepiece combos?
>>
>> Nick
>>
> Nick, Ya, it's really a good idea to buy from a local dealer. If push
> comes to shove you walk into the dealers office and stand there until
> someone pays attention to you.
>
> Stereo buyers come in a lot of flavors. I own a pair of 30X (!) Wild
> eyepieces. I doubt that anyone would buy them but... There are some
> purchasers that need stereos to do things that I doubt you are doing. The
> usual one is visuallizing wires that attach to the chip. You need the 3-D
> to see the chip-wire attachment and you need to exceed the 1000 to 1 ratio
> (NA to magnification) that is the usual limit because there is no other
> way. If there was a better way to do it, everybody would do it.
>
> There is a delicate balancing act between NA and mag for these users.
> Should you gain mag and NA but loose working distance by going to a higher
> mag front lens or keep working distance and NA and use higher mad
> eyepieces? You've gotta work this one out for your purposes yourself.
> Personally I like lots of NA but I'm not doing things like you are.
>
> I can remember being at some industrial sites and going through the
> rational for a high mag instillation. The problem was to come to some
> style of thing that left the user with high NA, 3-D and a lot of working
> distance. Mostly we had to use a stereo that just didn't "look" to good.
>
> Or to put it another way, if it looks good, it looks good.
>
> Kevin Cunningham
> SMS
>


.