"Crop-ability" of images?

Started 5 months ago | Discussions thread
Muster Mark Contributing Member • Posts: 588
Re: "Crop-ability" of images?

bobn2 wrote:

Muster Mark wrote:

bobn2 wrote:

dperez wrote:

More photographers who’s judgement I respect are talking about moving to Olympus. A question came up the other day and I’m trying to figure out the answer.

Nikon D850, 600mm f/4 versus M1X, 300mm f/4.

As I understand it - the lenses are the same equivalent - 600mm. The Nikon shoots at f/8 and ISO 3200 and 1/500. The M1X shoots at f/4 so the DOF is the same, and ISO 800 and 1/500, so the exposure is the same, right?

Wrong! Somewhere along the way you've picked up a wrong idea of what 'exposure' means. It does not mean how light or dark the image is. It means what is the light energy density at the sensor. It is determined by shutter speed, f-number and scene luminance. In your example, since the shutter speed and scene luminance are the same, but the f-number is two stops higher on the Nikon, it will have two stops less exposure. But it will make up for it by having four times the sensor area.

I think he was saying he puts the Nikon at f8 and gets the same results as the Oly at F4. This is correct. He has the Nikon shooting at ISO 3200 and the oly at ISO 800. I don't think your criticism of his understanding is warranted.

I didn't criticise his understanding except for the meaning of 'exposure', which he got wrong. This misunderstanding is unfortunately common. As you say, if he was saying that he gets the same 'results' or lightness, then yes, he's right.

This was a nuance I was unfamiliar with. Now I know!

-- hide signature --

Cheers,
-Ian

 Muster Mark's gear list:Muster Mark's gear list
Olympus E-3 Olympus Zuiko Digital ED 50mm 1:2.0 Macro Olympus Zuiko Digital ED 12-60mm 1:2.8-4.0 SWD Olympus Zuiko Digital ED 50-200mm 1:2.8-3.5 SWD
Post (hide subjects) Posted by
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow