Talking focal lengths

[HouseACA]

Hi

My first post here and was hoping for some help.

I'm only really starting photography and have just been reading a magazine and a question came to me.

When I see a photo I like in the magazine I look at the technical details to see if I could recreate it. But when I see the focal length is it for that camera? Knowing my camera has a crop factor of 1.5 do I need to also check the camera the magazine photo is taken with to make sure I'm comparing like for like. 35mm on my camera may be closer to the 50mm as per the magazine photo.

I suppose in short I'm asking do you quote what the length you took on your camera or the 35mm equiv?

Thanks all.

House

[DigiDiva]

Welcome and wish I could answer you but, its something I don't understand myself so will look with interest at the replies

[wavemachine]

Hi and welcome,

The focal length quoted is normally what the physical focal length was set on the lens when the picture was taken and does not include the crop factor.

So you do quote the focal length that was set on the lens and not the 35mm equivalent.

[markgozz]

Originally Posted by HouseACA

Hi



I suppose in short I'm asking do you quote what the length you took on your camera or the 35mm equiv?

Thanks all.

House

The short answer is you quote the focal length of the lens no matter what your camera.

The long answer could and does go on for ever .

Mark

Sorry Dave your reply wasn't there when I started .

[HouseACA]

Thanks for the replies. I suppose the answer seems obvious now.

[rbarry]

As above.

If you are able to, and if it's been included as data within the jpeg image file, then check the exif data. This may tell you the camera body that was used and the setting of the focal length of the lens used to capture that specific image.

[jet_kit]

Hi House & welcome.

Reading your post I think you may be asking a slightly different question to that which has been answered.
They're all correct when they say that the focal length is the focal length is the focal length. What changes is the effect of that on the particular camera it's used on.
Professional DSLRs use what is termed 'Full Frame' sensors. These are the same size as the old 35mm film format (24mm x 36mm), while lower-end Nikons use a sensor16mm x 24mm and Canon15mm x 22.5. From this is derived the 'Crop Factor' If you multiply the sensor size by the crop factor you end up with the 'full frame'. All sounds terribly techie and useless, but it is important to know where your starting point is.
With full frame a 50mm focal length lens is generally considered to be the standard lens. This is because the perspective it provides is close to that seen by the human eye. Shorter focal lengths are termed Wide Angle and accentuate the perspective (objects appear further apart), while longer focal lengths (Telephoto) compress the perspective.
With most DSLRs you will need to apply the crop factor to determine where the focal length you're using lies. As you rightly say 35mm multiplied by 1.5 equals 52.5mm which is pretty well 'Standard'.
So, if the picture you're looking at in the mag is taken with a pro camera and say 150mm lens; to recreate that image with a crop DSLR you will need a 100mm lens
If, however, you're using a Bridge camera with no interchangeable lens, they tend to use 'Equivalent' focal lengths and 50mm will be the 'Standard' focal length setting.
Hope this helps.

[HouseACA]

Thank you for the reply jet kit.
Yes I am using a dx Nikon so having do a bit of quick maths when thinking about the focal lengths.

When i looked at the data in the mag it would say 200mm with canon xx model etc, then id have to look up that camera to see if its full frame or not. I guess I just have to assume the photos I see in the mags are using a full frame and adjust accordingly.

[rbarry]

Bear in mind that the photo data you read will be how that image was captured at the time. It won't tell you how the image has been manipulated in post processing; there's every chance it may have been cropped by the author/editor afterwards.