CP 5700: Fixed Aperture???

[horizoner]

Hi Guys!!

I own a Nikon CP 5700 for almost a yr but there's a particular setting which I'm totally clueless about.

Under one of the menu in "Zoom", there's a On/Off setting for "Fixed Aperture". When set to on, what difference does it make?

Hope it's not another bug that has gone unnoticed :dunno:

Wil appreciate any advice

Derrick

 

[horizoner]

Forgot to mention that I don't have the manual with me ...

 

[Fella]

"
Fixed Aperture
Normally, aperture changes with the zoom position. If desired, you can set the camera to maintain the f/number selected in aperture priority or manual exposure modes as you zoom in or out.
"

 

[horizoner]

Hi Fella,

That's what I thought. But let say I shoot in Aperture Priority and f/n 2.8. When I zoom in ... the f/n will change to 4.2 when zoom in fully (with Fixed Aperture on).

Since u own this cam too .. do u face this too?

 

[Fella]

"
In aperture priority and manual exposure modes, aperture is fixed at selected f/number as camera is zoomed in or out. Note that the selected f/number may exceed the camera's exposure range at the new zoom position; to prevent this, choose an f/number from about f/5 to around f/8.
"

I've personally never made use of the function but since you mentioned it, had did some tests.
What I discovered is that the camera will still adjust the aperture slightly (if what you've selected is without the cam's exposure range) when you zoom all the way in, but will revert to the f/number you've set when you zoom out.
That's with the fixed aperture feature set to on.

If it's set to off, when you zoom back out to full wide, very likely the cam will also change the f/number to something else.

IMO, that's not too much of a concern to me since I don't find the feature useful.

 

[horizoner]

I was hoping that it can maintain at 2.8 even at tele so that i can achieve a shallower DOF for portrait.

Forget it then ..

Thanks so much for the explanation.

 

[denizenx]

Originally posted by horizoner
I was hoping that it can maintain at 2.8 even at tele so that i can achieve a shallower DOF for portrait.

Forget it then ..

Thanks so much for the explanation.

f/2.8 at full tele? not from nikon... ;p
anyway it's a physical design limitation of the camera, so it's not a bug..

 

[Nutcase]

Yes. even with traditional SLR zoom lenses (especially from Nikon) the f. stop is expressed in a range eg f2.8-5.6

This means that f2.8 is only applicable at the shortest focal length and the aperture gets smaller and slides into f5.6 as you zoom into tele mode.

Problem with zoom lenses. But it has been a while since, I am not sure if this same limitation also applies to new lenses nowadays.

 

[taker]

Originally posted by Nutcase
Yes. even with traditional SLR zoom lenses (especially from Nikon) the f. stop is expressed in a range eg f2.8-5.6

This means that f2.8 is only applicable at the shortest focal length and the aperture gets smaller and slides into f5.6 as you zoom into tele mode.

Problem with zoom lenses. But it has been a while since, I am not sure if this same limitation also applies to new lenses nowadays.

Canon, Pentax, Minolta also got such lens, not just Nikon. Zoom lens with variable aperture are manufacture by all of them. More new zoom lens offer fixed aperture these days.

 

[horizoner]

yup ... I m just wondering that if apperture is maintained at f2.8 even at tele, then it will cause something like vignetting?

anyway ... thanks for all the info guys! Great to have experts around here. haha

 

[mpenza]

There's only one digital camera with a fixed aperture zoom lens - Panasonic DMC-FZ1 with a 35-420mm F2.8 constant aperture leica lens.

 

[munfai]

Originally posted by taker
Canon, Pentax, Minolta also got such lens, not just Nikon. Zoom lens with variable aperture are manufacture by all of them. More new zoom lens offer fixed aperture these days.

typically fixed aperture zooms are larger, heaver, and more expensive