Aperture...?!?

Dr.Louis

Hey guys, I have a question about aperture settings on a 50mm lens I have. It's a completely manual lens for a completely manual camera- no fancy stuff!

Basically I'd like to know how to tell what aperture setting I have the lens on when it's between the indicated settings- the lens has the following settings marked on it-

1.7, 2.8, 4, 5.6, 8, 11, 16 and 22

But it has more settings than just the 8 mentioned (14 in total), so if the line is pointing to an area between two f numbers, how do I know what settings it's on?

Might be a silly question, but it has me baffled because all the intervals are different!

Cheers! Louis.

trishw78

Does the lens have a manual/booklet. I'd quess half a size bigger than the first and half a size smaller than the next. If that makes sense.

thefizz

I'd guess you can set your aperture at half stops between the indicated f-stop numbers.

5uspect

Can you feel a physical notch between indicated stops?
I'd imagine they're equally spaced between those indicated.

rahtkennades

Dr.Louis wrote:

Hey guys, I have a question about aperture settings on a 50mm lens I have. It's a completely manual lens for a completely manual camera- no fancy stuff!

What camera is it for?

Dr.Louis wrote:

Basically I'd like to know how to tell what aperture setting I have the lens on when it's between the indicated settings- the lens has the following settings marked on it-

1.7, 2.8, 4, 5.6, 8, 11, 16 and 22

But it has more settings than just the 8 mentioned (14 in total), so if the line is pointing to an area between two f numbers, how do I know what settings it's on?

Might be a silly question, but it has me baffled because all the intervals are different!

Cheers! Louis.

Does it 'click' between the stops, or does it turn smoothly?

You're fully sure you mean the aperture ring? As in, there should be two rings, one aperture (usually clicks between f/-stops) and one for focus (runs smooth). Sometimes the f/-numbers will be shown on the base of the focus ring as well (see below).
[IMG][/img]http://farm1.static.flickr.com/28/45019585_5367361642_o.jpg

It's a head-scratcher!

leinsterman

The numbers represent 1 full stop (i.e. each one is letting in half as much light as the previous from at least from f2.8 onwards to 22 ... not sure what f1.7 is about since in relative terms it is not a multiple of a full stop away form f2.8)

... so by the looks of it the in between graduations are half stops ...

Here is the wiki for it -

http://en.wikipedia.org/wiki/F-number

ThOnda

You'll know that for sure when you set your camera to Av mode and try to hold the same scene and change aperture. If the camera set's longer time in the position "inbetween", you are lucky man! If the setting of the time is not precise, changes a lot, don't use those positions.
I have read that apertures are in two lines. One with base "1" and the second with base "1.4". It has something to do with mathematical equation of the amount of the light going through the lense when the shutter is opened. But I don't understand exposure, so don't ask me :-)

Dr.Louis

ThOnda wrote:

You'll know that for sure when you set your camera to Av mode and try to hold the same scene and change aperture.

It's a fully manual camera- I aint got no fancy modes! hehe

well basically there's a click for every number indicated and a click for every position inbetween any two numbers and as the spacing between each indicated f stop isn't actually equal to the next I'm just finding it hard to work out what f number I'm actually on... If that makes sense...? lol

And it's a Phenix camera- 50mm lens. It says the lowest f number is f1.7 But I'm inclined to think that's a mistake and it should be f1.8 or something...

magicbastarder

no reason why it can't be at f1.7; the jump from f1.8 to f2.8 isn't an exact stop, anyway. to go up a stop from f1.8 would be to f2.54...

also, i've seen other lenses where the aperture ring works in half stops.

ThOnda

f is for aperture f/1.7, f/2, f2.4...

If it is OLD camera, so there are certainly regular stops between signed positions on the lense. Don't worry about it, it is going to give you more precise setting of exposure, because you are limited by preset shutter times.

And the lowest aperture (the biggest hole) is done by construction, so it could be any number. Even "1" (one for non-believers). So it is not missprint.

Enjoy so fast lense!

magicbastarder

the beast appears again:

ThOnda

That is bigger hole than in my.... well, middle format camera!

rahtkennades

Is this the puppy?

http://www.astronomy.ie/phenix.html

It's all I can find on it!!

Fajitas!

There is a Leitz 50mm f/0.75, and I remember a f/0.65....

Google dosn't throw up much though.

But I just thought you speed freaks might be interested.

ThOnda

Bloody Chinesee, they must copy everything!
http://www.chine-taiwan.com/phenixoptics.htm

Hmmm, how much for their copy of Horizon?

EDIT: Just read it once more. That is funny:
... with more than 4500 staff, 700 engineers and technicians serving 150 customers all over the world.

They have 150 Customers! And one is in Ireland, obviously ;-)

deRanged

ThOnda wrote:

They have 150 Customers! And one is in Ireland, obviously ;-)

there may well be two more in Cork - two camera shops here have a Phenix for sale. I almost bought one but went for a Vivitar from Amazon.co.uk instead. Strangely enough, it's got a f1.7 lens too.