Same settings but different cameras?

[JJ84]

Dear All,

Just wondering whether the outcome (that is, the pictures that are taken) would/should be the same if I apply the same settings in 2 different cameras

For example, I have set both to AV (Aperture priority), set the f-stop to f/5 and used a focal length of 55mm. However, the picture that result does not show the same depth of field. Is that to be expected or is there something that I am missing here?

The cameras are: Fujifilm HS20 and the Sony A35

Thank you
Javed

[xpatUSA]

Dear All,

Just wondering whether the outcome (that is, the pictures that are taken) would/should be the same if I apply the same settings in 2 different cameras

For example, I have set both to AV (Aperture priority), set the f-stop to f/5 and used a focal length of 55mm. However, the picture that result does not show the same depth of field. Is that to be expected or is there something that I am missing here?

The cameras are: Fujifilm HS20 and the Sony A35

Thank you
Javed

Are the sensors the same size in mm and was the distance to the subject the same and was the subject's image size in mm the same at the sensor (i.e. in the image plane)? If not, the depth of field will be different, I reckon.

[William W]

What Ted suspected.

The Fuji is about a 1/2.33" sensor (about 6.4mm x 4.8mm) and the Sony is a "Sony" APS-C sized sensor (about 23mm x 15mm).

So (rough calculations):

1. if you had a 55mm lens on the Sony Camera, you'd need about a 15mm lens on the Fuji to get the same Angle of View.

2. if you set F/5 on the Sony Lens, you'd need to set about F/1.3 on the Fuji, to get the same Depth of Field.

WW

[JJ84]

Are the sensors the same size in mm and was the distance to the subject the same and was the subject's image size in mm the same at the sensor (i.e. in the image plane)? If not, the depth of field will be different, I reckon.

Thank you for the quick reply
William W replied to your question on sensor size. Everything else you asked was same.

Thanks
Javed

[JJ84]

What Ted suspected.

The Fuji is about a 1/2.33" sensor (about 6.4mm x 4.8mm) and the Sony is a "Sony" APS-C sized sensor (about 23mm x 15mm).

So (rough calculations):

1. if you had a 55mm lens on the Sony Camera, you'd need about a 15mm lens on the Fuji to get the same Angle of View.

2. if you set F/5 on the Sony Lens, you'd need to set about F/1.3 on the Fuji, to get the same Depth of Field.

WW

Thank you William W,

This makes a lot of sense. Thank you for the quick reply.

Javed

[William W]

Thank you William W, This makes a lot of sense.

It’s fairly common and most people are reasonably versed in using what is commonly referred to as “crop factor” if you want to translate lens’s Focal Length to an equivalent, in Field of View for different Camera Formats.

For example if you plonk a 50mm lens on a Canon 70D that lens will act as a short telephoto lens – some people will say: “it is equivalent to an 80mm lens on a Full Frame Camera, because the ‘crop factor’ is 1.6”.

*

But when swapping between Camera Formats I am sometimes interested in the DoF comparatives. When I do need to consider DoF, I think of that in terms of Aperture “Stops” that I will need to open (or close) to get approximately the same DoF.

As a ROUGH guide – and referring ONLY to DIGITAL CAMERAS (i.e. NOT Film Formats) here is a list of DoF ‘Stop Values’ based around a 135 Format Camera (commonly known as “Full Frame” in the digital world)

Digital ‘Medium Format’ (e.g. Mamiya ZD) -1 Stop
Digital ‘645 Format’ (e.g. Pentax 645D) -⅔ Stop
135 Format (e.g. Canon 5D Series / Nikon D3) 0 Stop
APS-H Format (e.g. Canon 1D Series) +⅔ Stop
APS-C Format (aprx. for Can/Nik/Pen/Fuji/Sigma) +1⅓ Stop
4/3 Format (Olympus/Panasonic) +2 Stop
All Sub-miniature Formats (aprx. for all P&S & Bdge) +5 Stop
i-phone +6 Stop

So, for example, if you want to get the same DoF (for the same Framing and Subject Distance), you SUBTRACT the format you move to, from the format you came from.

So if you take a photo with a Canon 5D (135 Format) and use F/2.8 and then move to a Canon 60D (APS-C Format) the calculation is:
(0 - 1⅓) = -1⅓
(a minus sign in the answer means you have to OPEN the Lens’s Aperture).

So that means you’ll need to use about F/1.8, on your APS-C Camera, to get the same DoF when using F/2.8 on your 'Full Frame' Camera.

WW