Olympus UK E-System User Group
Olympus UK E-System User Group

Join our unique resource for Olympus Four Thirds E-System DSLR and Pen and OM-D Micro Four Thirds photographers. Show your images via our free e-group photo gallery. Please read the e-group.uk.net forum terms and conditions before posting for the first time. Above all, welcome!


Go Back   Olympus UK E-System User Group > Cameras, lenses and system accessories > Camera conference > Micro Four Thirds

Micro Four Thirds Discuss the newly announced Micro Four Thirds addition to the Four Thirds system family here.

Reply
 
Thread Tools Display Modes
  #1  
Old 3rd February 2014
Paul19's Avatar
Paul19 Paul19 is offline
Full member
 
Join Date: Mar 2011
Location: In the mountains west of Sydney, Australia
Posts: 186
Thanks: 42
Thanked 25 Times in 20 Posts
Likes: 80
Liked 9 Times in 8 Posts
Same f stops on f/f as 4/3?

Some clarifying information please!
I have heard conflicting opinions that the depth of field reach on 4/3 cameras is double that of a full frame camera for the same f stop.
One arguement goes that as the 4/3 sensor is half the size of a f/f sensor then the lens reach is doubled. That is, a 25mm lens on 4/3 has the same reach as a 50mm on f/f. So it is argued that the same applies for f stops: f4 on a f/f camera is equal to f8 on a 4/3 camera.
The opposite arguement is that because each aperture is a mathematical equation and relates to a lens and not a sensor, then f4 on a f/f camera is identical to f4 on a 4/3 camera thus providing the same depth of field.
Can anyone help to clarify this?
__________________
Paul
Reply With Quote
  #2  
Old 4th February 2014
sponner sponner is offline
Full member
 
Join Date: May 2011
Location: Staffordshire Moorlands
Posts: 1,211
Thanks: 12
Thanked 164 Times in 143 Posts
Likes: 7
Liked 28 Times in 21 Posts
Re: Same f stops on f/f as 4/3?

I to oam confused by dof but it I think you are right, 4/3 produces greater dof at equivalent focal lengths.

try this and put in 50mm for ff and 25 mm for 4/3

http://www.dofmaster.com/dofjs.html
__________________
hearts at peace under an English heaven
Reply With Quote
  #3  
Old 4th February 2014
alfbranch's Avatar
alfbranch alfbranch is offline
Full member
 
Join Date: Oct 2012
Location: Whitehaven Cumbria
Posts: 6,819
Thanks: 1,596
Thanked 806 Times in 763 Posts
Likes: 1,216
Liked 2,761 Times in 947 Posts
Re: Same f stops on f/f as 4/3?

You need to remember that the phrase Full Frame is a Canikon bullshit term for a start.
As would 10" X 8" not really be full frame?

4/3 is full frame as it is not a cut down format using another formats lenses.

The smaller the format used the greater the depth of field is acheved generally at any given aperture but that said it is more complicated than that. On a 10" X 8" camera aperture of 128 are not unheard of but on 4/3 they are not an option due to diffraction so we only get f22.
My Xz-1 compact only goes to f8 for the same reason.

I suspect you are also confusing the angle of view on any given focal length on each format. In terms of angle of view a 50 lens on a 35mm format is the same as 25 mm lens on a 4/3 sensor. The same angle of view on medium format is around 80mm depending teh camera in question.
__________________
OMD E-M1 OMD E-M5II MMF3 12-40 pro 12-50 EZ 14-42 EZ 9-18 f4.0 -5.6 40 -150f4-f5.6 R 60mm f2.8 macro Sigma 105 f2.8 macro Holga 60mm plastic Holga pinhole lens lens and a XZ-1 Olympus - 35 SP Trip 35 Pen EEs OM2sp

I nice view does not mean a good photograph. My FLickr

Reply With Quote
The Following User Says Thank You to alfbranch For This Useful Post:
Paul19 (4th February 2014)
The Following Users Liked This Post:
Greytop (10th April 2015), Jim Ford (28th January 2016)
  #4  
Old 4th February 2014
pvasc pvasc is offline
Full member
 
Join Date: Apr 2012
Location: UK
Posts: 684
Thanks: 90
Thanked 139 Times in 112 Posts
Likes: 61
Liked 102 Times in 60 Posts
Re: Same f stops on f/f as 4/3?

From the Olympus E-30 manual. The only place I have come across in all the Olympus manuals that explained this.

"Depth of Field
A Four Thirds system camera can achieve a depth of field equivalent to two times deeper than that of a 35-mm camera. A Four Thirds system lens with f2.0 brightness, for example, is equivalent to f4.0 when converted to the aperture of a 35-mm camera."

As far as light let in F stops are equal.
Reply With Quote
The Following User Says Thank You to pvasc For This Useful Post:
Paul19 (4th February 2014)
  #5  
Old 4th February 2014
gazza95 gazza95 is offline
Full member
 
Join Date: Sep 2008
Location: Oxford
Posts: 199
Thanks: 11
Thanked 44 Times in 27 Posts
Likes: 8
Liked 18 Times in 13 Posts
Re: Same f stops on f/f as 4/3?

Hi Paul

There are essentially two parts to this discussion;

1) Field of view, as others have said to get the same FOV on a 43 camera as a FF camera you need to use a lens of half the focal length. This gives an increased depth of field.

2) Circle of Confusion. This is essentially how out of focus a point can be yet appear sharp in final image. This is a factor of how much an image needs to be enlarged for a give print size. 43 needs to be enlarged twice as much as ff.

The rule of thumb is for same FOV a 43 gives you 2 stops more DoF as FF.

Using a DoF calculator such as

http://www.dofmaster.com/dofjs.html

is a good way of seeing the effect of these two parameters.

Gary
Reply With Quote
The Following User Says Thank You to gazza95 For This Useful Post:
Paul19 (4th February 2014)
  #6  
Old 4th February 2014
Paul19's Avatar
Paul19 Paul19 is offline
Full member
 
Join Date: Mar 2011
Location: In the mountains west of Sydney, Australia
Posts: 186
Thanks: 42
Thanked 25 Times in 20 Posts
Likes: 80
Liked 9 Times in 8 Posts
Re: Same f stops on f/f as 4/3?

Thanks all for your imput.

So in summary, correct me if I'm wrong - If I use a 4/3 camera with a 45mm lens at f11 then this will give me the same DoF as a f/f camera with a 90mm lens at f22.
__________________
Paul
Reply With Quote
  #7  
Old 5th February 2014
gazza95 gazza95 is offline
Full member
 
Join Date: Sep 2008
Location: Oxford
Posts: 199
Thanks: 11
Thanked 44 Times in 27 Posts
Likes: 8
Liked 18 Times in 13 Posts
Re: Same f stops on f/f as 4/3?

Yes, thats the right.
Reply With Quote
  #8  
Old 5th February 2014
Ian's Avatar
Ian Ian is offline
Administrator
 
Join Date: Jul 2007
Location: Hemel Hempstead, Hertfordshire, UK
Posts: 11,590
Thanks: 425
Thanked 2,525 Times in 1,272 Posts
Likes: 870
Liked 1,706 Times in 773 Posts
Re: Same f stops on f/f as 4/3?

Basically, yes - you will get twice as much depth of field with Four Thirds compared to Full frame - the DOF is proportional to the diagonal of the frame (diameter of the image circle) and the field of view (comparable focal length) and the aperture. But on the other hand the brightness for a given aperture is identical, no matter what the frame size, so f/1.8 on any lens from any system would give the same exposure at the same given shutter speed and ISO sensitivity as any other setup using the same aperture, etc.

So:

Four Thirds vs Full Frame

FT 45mm f/11 vs FF 90mm f/22 (same field of view, same DOF, but the full frame is four times (2 stops/EVs) darker)

But:

FT 45mm f/11 vs FF 45mm f/22 (FF is wider field of view and FF has 4.7x MORE DOF as well as four times darker)

FT45mm f/11 vs FF 90mm f/11 (same field of view, same brightness, FF has half the DOF)

Don't get too hung up about dof; if a full frame set up is achieving a couple of cm of DOF for out of focus effect, Four Thirds will only increase that to 4cm, which remains very limited and this can often be compensated for by using a longer focal length or tighter framing.

Ian
__________________
Founder and editor of:
Olympus UK E-System User Group (http://e-group.uk.net)
Four Thirds User (http://fourthirds-user.com)
Digital Photography Now (http://dpnow.com)
Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

Twitter: www.twitter.com/ian_burley
Flickr: www.flickr.com/photos/dpnow/
Pinterest: www.pinterest.com/ianburley/
NEW: My personal BLOG ianburley.com

Last edited by Ian; 5th February 2014 at 10:05 AM. Reason: More info added and corrections
Reply With Quote
The Following User Says Thank You to Ian For This Useful Post:
Paul19 (5th February 2014)
  #9  
Old 5th February 2014
byegad byegad is offline
Full member
 
Join Date: Oct 2013
Location: NE England
Posts: 771
Thanks: 20
Thanked 99 Times in 93 Posts
Likes: 106
Liked 151 Times in 105 Posts
Re: Same f stops on f/f as 4/3?

f11 is f11 is f11. It's a measure of the diameter of the hole that is opened to the sensor when you fire the shutter. So f11 and 1/250s is the same amount of light getting through for all formats.

As has been said the effect of using f11 on DoF will be different for full size sensors 1.6 crop sensors and 2.o crop sensors.

I find my f# is dictated by the speed of shutter I need for a shot (I predominately shoot wildlife where the critters move!) and DoF is left to take care of itself. If you are taking Portraits where a short DoF is desirable or Landscapes where a big DoF is preferred then you have the advantage that the subject is stationary so you then will pick an f# to get DoF and let shutter speed take care of itself.
__________________
Too many cameras!
E-500, E-510, EPM1, EPL5, EP3, EP5, OM-D E M10, OM-D E M5, Trip 35mm, Samsung WP10 and Panasonic G6 plus lots of lenses many manual focus.

Photos at http://www.flickr.com/photos/42941818@N07/
Reply With Quote
  #10  
Old 5th February 2014
Paul19's Avatar
Paul19 Paul19 is offline
Full member
 
Join Date: Mar 2011
Location: In the mountains west of Sydney, Australia
Posts: 186
Thanks: 42
Thanked 25 Times in 20 Posts
Likes: 80
Liked 9 Times in 8 Posts
Re: Same f stops on f/f as 4/3?

Quote:
Don't get too hung up about dof; if a full frame set up is achieving a couple of cm of DOF for out of focus effect, Four Thirds will only increase that to 4cm, which remains very limited and this can often be compensated for by using a longer focal length or tighter framing.

Ian
That puts it all into perspective!
Thanks eveyone
__________________
Paul
Reply With Quote
  #11  
Old 5th February 2014
Ian's Avatar
Ian Ian is offline
Administrator
 
Join Date: Jul 2007
Location: Hemel Hempstead, Hertfordshire, UK
Posts: 11,590
Thanks: 425
Thanked 2,525 Times in 1,272 Posts
Likes: 870
Liked 1,706 Times in 773 Posts
Re: Same f stops on f/f as 4/3?

Taken at f/1.8 using the m.Zuiko 17mm f/1.8 this evening. Even with a semi-wide angle lens you can get creative limited DOF:



Ian
__________________
Founder and editor of:
Olympus UK E-System User Group (http://e-group.uk.net)
Four Thirds User (http://fourthirds-user.com)
Digital Photography Now (http://dpnow.com)
Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)

Twitter: www.twitter.com/ian_burley
Flickr: www.flickr.com/photos/dpnow/
Pinterest: www.pinterest.com/ianburley/
NEW: My personal BLOG ianburley.com
Reply With Quote
  #12  
Old 14th May 2014
rich_ rich_ is offline
Full member
 
Join Date: May 2014
Location: Essex
Posts: 74
Thanks: 0
Thanked 2 Times in 1 Post
Likes: 0
Liked 9 Times in 8 Posts
Re: Same f stops on f/f as 4/3?

I'm finding it very useful using a M4/3 Camera after using just FF for a while. At night on a wide aperture lens it has proven to be very difficult to get pictures of my friends unless they stand in a uniform line! With a comparable aperture M43 lens no problem, yet I still receive all the light!
Reply With Quote
The Following User Liked This Post:
Ian (14th May 2014)
  #13  
Old 10th April 2015
Petrochemist Petrochemist is offline
Full member
 
Join Date: Apr 2015
Location: N Essex
Posts: 735
Thanks: 36
Thanked 83 Times in 76 Posts
Likes: 215
Liked 129 Times in 94 Posts
Re: Same f stops on f/f as 4/3?

Quote:
Originally Posted by byegad View Post
f11 is f11 is f11. It's a measure of the diameter of the hole that is opened to the sensor when you fire the shutter. So f11 and 1/250s is the same amount of light getting through for all formats.
A minor quibble, it's not the diameter of the hole itself but the number of times the diameter of the hole goes into to the lenses focal length. A ratio - which is why the number gets smaller s the opening increases.
Reply With Quote
The Following User Liked This Post:
Greytop (10th April 2015)
  #14  
Old 28th January 2016
Harold Gough Harold Gough is offline
Full member
 
Join Date: Oct 2014
Location: Reading UK
Posts: 5,813
Thanks: 58
Thanked 818 Times in 747 Posts
Likes: 40
Liked 3,244 Times in 1,749 Posts
Re: Same f stops on f/f as 4/3?

Consider a x1.4 TC and a x2 crop sensor.

The TC selects the image from the centre of the lens and spreads it over the sensor. However, "rays" of light from the centre of the lens are more parallel than at the edge, hence more DOF but at the cost of one stop of exposure.

The crop sensor collects light at the same intensity as a larger sensor but, if the camera is fitted with a lens with an image circle for larger format, will collect "rays" from the centre of the lens, which are more parallel and give more DOF, but at no cost of exposure.

Harold
__________________
The body is willing but the mind is weak.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
A Crimson Rosella stops by to say "hello". Ross the fiddler Foto Fair 44 17th July 2012 11:30 PM
For sale 58mm Vari ND Filter (2-8 stops) DekHog For sale or wanted small ads 12 9th November 2011 09:07 PM
Everything stops for tea ... Ann1e Foto Fair 21 20th May 2011 03:16 PM
Roadside Stops pandora The lounge 5 18th April 2011 06:53 AM
demo - f-stops / ISO / shutterspeed / light levels Ellie Camera conference 4 7th February 2008 12:01 AM


All times are GMT. The time now is 07:22 AM.


The Write Technology Ltd, 2007-2019, All rights reservedAd Management plugin by RedTyger