I better do something photographic tonight!
Two stops - that's two clicks up on the lens. So f2-f2.8-f4. So if
you use a 2x teleconverter to make a 50mm f1.8 lens into a 100mm its
maximum aperture will be about f3.7.
That 3.8 Hanimex (probably closer to f4) with a 3X is three stops up
so max aperture should be f11 or a hair under. That's pretty dim.
F stops were based on the original Waterhouse stops I think (Metal
plates with holes of various diameters) and is a logrithmic scale -
1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 64.
Andrew Fildes
afildes@xxxxxxxxxxxxx
On 27/02/2007, at 8:49 PM, Scott Peden wrote:
>
> I got it 'cheap' last month, less than a 20 dollar bill after
> shipping, I
> had only put a bid on it to watch it, and on occasion I get stuff that
> cheap.
>
> I didn't understand everything you mentioned.
> Using a 3.8 lens, that would make it about a 6.3 right?
> Using a f8 it would be a f10?
>
> Actually I know I didn't understand, the confusion must be 'stops'.
>
> How many numbers is an F stop? Or is this that 1.4 times itself thing?
>
> I have a 2 X Vivitar too, rather nice considering it isn't a Zuiko,
> but it
> does lose some clarity, I didn't check it out across the room
> against the 3
> X, maybe I can do that during the thunderstorms tomorrow hen I
> don't want to
> be outside.
>
> Ahh.. I have a book and I understood something, it is the 1.4
> thingy. SO I
> multiply 3.8 or 8 times 1.4, two times to get an idea of where my
> new F stop
> is likely to be.
>
> f3.8 x 1.4 = 5.32 x 1.4 = 7.5... acceptable if the glass is any
> good.....
> f8 x 1.4 = 11.2 x 1.4 = 15.7 that's going to be fun......
>
> And again, my shutter speed should be 1/the lens mm?
> So a 210 mm lens with 3 x teleconverter should have a shutter speed
> somewhere around 1/600?
>
> Scott
>
>
>
> -----Original Message-----
> From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On
> Behalf
> Of Piers Hemy
> Sent: Tuesday, February 27, 2007 1:28 AM
> To: olympus@xxxxxxxxxx
> Subject: spam: [OM] Re: Vivitar Automatic Tele Converter 3X-21
>
>
> I remember getting a 3x TC decades ago, thinking it woul be the
> answer to
> not being able to afford longer lenses. It will cost you 2.5 stops
> by my
> reckoning - an f/2 aperture will have the effect of f/6; an f/4
> the effect
> of an f/12.
>
> Do I sound very unenthusiastic?
>
> --
> Piers
>
>
> -----Original Message-----
> From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On
> Behalf
> Of Scott Peden
> Sent: 27 February 2007 06:43
> To: Scott Peden
> Subject: [OM] Vivitar Automatic Tele Converter 3X-21
>
>
> Can anyone tell me what quality this is? It is 58 mm long or 2.25
> inches
> long.
>
>
>
> Anyone know how many F stops I lose when I use this?
>
>
>
> I tried googleing this a couple of times and can't find out anything.
>
>
>
> I just put it on a 3.8f 210 mm Haminex lens and the initial tests
> (indoors,
> corner to corner in my bedrooms) amazed me, I thought I was using
> my nicer
> 2X Vivitar lens that is about 1.5 inches thick. I've got to have good
> weather to try this out where I have been shooting the Red
> shouldered hawk.
>
>
>
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