f/5.8 lens on a camera setting of f/5.6

McLaughlin · 03-13-2021, 10:04 AM

What effect has a lens aperture of f/5.8 on a camera that has only a setting of f/5.6?

Lord Lucan · 03-13-2021, 10:12 AM

Nothing significant I guess. But what camera and what lens is this?

McLaughlin · 03-13-2021, 10:33 AM

A Pentax K20d camera and a Pentax SMC DA L 55-300mm Zoom

**Bob 256** · 03-13-2021, 11:02 AM

If in fact there is a difference, it's only 7% which for exposure purposes, is just Lord Lucan stated, almost insignificant (more like insignificant).

Wheatfield · 03-13-2021, 11:03 AM

Originally posted by McLaughlin

What effect has a lens aperture of f/5.8 on a camera that has only a setting of f/5.6?

Effectively nothing.

kypfer · 03-13-2021, 11:06 AM

Originally posted by McLaughlin

What effect has a lens aperture of f/5.8 on a camera that has only a setting of f/5.6?

The metering will take it all into account, irrespective of the numbers printed on the lens. If necessary the camera will set a slightly longer shutter speed than might be expected at f/5.6 … other than that you'll not notice a difference

Enjoy!

Fogel70 · 03-13-2021, 11:12 AM

In this case I believe the only thing to worry about is that EXIF info in the images will say f/5.6 instead of f/5.8.

McLaughlin · 03-13-2021, 12:24 PM

Thanks for all your help.

pschlute · 03-13-2021, 01:01 PM

Originally posted by McLaughlin

A Pentax K20d camera and a Pentax SMC DA L 55-300mm Zoom

That lens has its aperture controlled from the camera. If the camera says it is using 5.6 where do you get 5.8 from ?

swanlefitte · 03-13-2021, 01:07 PM

Pentax cameras display f/4.5 for both the half step and third step but exposes properly. I would expect the same. A camera is only +/- a third step (edit: 1/6 stop, 1/3 to 1/2) anyway given limited aperture and shutter settings except in bulb mode.
Half-Step Aperture Value Incorrectly Labeled! - PentaxForums.com

Lord Lucan · 03-13-2021, 01:18 PM - **1 Like**

Originally posted by pschlute

If the camera says it is using 5.6 where do you get 5.8 from ?

Presumably from the nominal max aperture of the lens when zoomed to 300mm :
SMC Pentax-DA 55-300mm F4-5.8 ED Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database

**K(s)evin** · 03-14-2021, 02:00 AM

I have the DA 55-300 that has always done that to me. Also, my Bigma 50-500 f4-6.3 shows as f6.7 at full zoom wide open. I always figured it had something to do with having 1/2 or 1/3 stops set in camera.

03-13-2021, 10:04 AM	#1
McLaughlin New Member Join Date: Apr 2018 Location: Hoschton, Georgia Photos: Gallery \| Albums Posts: 8	f/5.8 lens on a camera setting of f/5.6 What effect has a lens aperture of f/5.8 on a camera that has only a setting of f/5.6?

03-13-2021, 01:07 PM	#10
swanlefitte Pentaxian Join Date: May 2015 Location: Minneapolis Photos: Gallery Posts: 4,068	Pentax cameras display f/4.5 for both the half step and third step but exposes properly. I would expect the same. A camera is only +/- a third step (edit: 1/6 stop, 1/3 to 1/2) anyway given limited aperture and shutter settings except in bulb mode. Half-Step Aperture Value Incorrectly Labeled! - PentaxForums.com Last edited by swanlefitte; 03-13-2021 at 06:04 PM.

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03-13-2021, 10:12 AM	#2
Lord Lucan Pentaxian Join Date: Sep 2017 Location: South Wales Photos: Gallery Posts: 2,978	Nothing significant I guess. But what camera and what lens is this?

03-13-2021, 10:33 AM	#3
McLaughlin New Member Join Date: Apr 2018 Location: Hoschton, Georgia Photos: Gallery \| Albums Posts: 8 Original Poster	A Pentax K20d camera and a Pentax SMC DA L 55-300mm Zoom

03-13-2021, 11:02 AM	#4
Bob 256 Site Supporter Join Date: Jun 2008 Location: Idaho Photos: Gallery Posts: 2,378	If in fact there is a difference, it's only 7% which for exposure purposes, is just Lord Lucan stated, almost insignificant (more like insignificant).

03-13-2021, 11:03 AM	#5
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,987	Originally posted by McLaughlin What effect has a lens aperture of f/5.8 on a camera that has only a setting of f/5.6? Effectively nothing.

03-13-2021, 11:06 AM	#6
kypfer Pentaxian Join Date: Jan 2018 Location: Jersey C.I. Posts: 3,597	Originally posted by McLaughlin What effect has a lens aperture of f/5.8 on a camera that has only a setting of f/5.6? The metering will take it all into account, irrespective of the numbers printed on the lens. If necessary the camera will set a slightly longer shutter speed than might be expected at f/5.6 … other than that you'll not notice a difference Enjoy!

03-13-2021, 11:12 AM	#7
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	In this case I believe the only thing to worry about is that EXIF info in the images will say f/5.6 instead of f/5.8.

03-13-2021, 12:24 PM	#8
McLaughlin New Member Join Date: Apr 2018 Location: Hoschton, Georgia Photos: Gallery \| Albums Posts: 8 Original Poster	Thanks for all your help.

03-13-2021, 01:01 PM	#9
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,217	Originally posted by McLaughlin A Pentax K20d camera and a Pentax SMC DA L 55-300mm Zoom That lens has its aperture controlled from the camera. If the camera says it is using 5.6 where do you get 5.8 from ?

03-13-2021, 01:18 PM - 1 Like	#11
Lord Lucan Pentaxian Join Date: Sep 2017 Location: South Wales Photos: Gallery Posts: 2,978	Originally posted by pschlute If the camera says it is using 5.6 where do you get 5.8 from ? Presumably from the nominal max aperture of the lens when zoomed to 300mm : SMC Pentax-DA 55-300mm F4-5.8 ED Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database

03-14-2021, 02:00 AM	#12
K(s)evin Site Supporter Join Date: Sep 2010 Location: Colorado Posts: 476	I have the DA 55-300 that has always done that to me. Also, my Bigma 50-500 f4-6.3 shows as f6.7 at full zoom wide open. I always figured it had something to do with having 1/2 or 1/3 stops set in camera.