"Crop-ability" of images?

Started 3 months ago | Discussions thread
john isaacs Veteran Member • Posts: 5,885
Re: "Crop-ability" of images?

bobn2 wrote:

john isaacs wrote:

bobn2 wrote:

john isaacs wrote:

Wu Jiaqiu wrote:

Donald B wrote:

bobn2 wrote:

Donald B wrote:

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.

I like this quote "The “Exposure Triangle,” as it is often referred to, is a handy way of interpreting the major components involved in the process of capturing an image.

Yes, I think that the 'triangle' is responsible for people thinking wrongly that the components of exposure are aperture, shutter and ISO.

well think of it like this , to expose a viewable image on the camera rear lcd or evf . the camera requires the correct aperture ,shutter speed and iso now try to argue against that

When invented by Bryan Peterson it was the 'Photographic Triangle'. Whatever the name, it's useless.

iso you say....the rabbit hole beckons

Exposure triangle:

https://www.cambridgeincolour.com/tutorials/camera-exposure.htm

That article is full of errors, as are many on that site. Argumentum ab auctoritate is a fallacy in any case, but when your authority doesn't know what it's talking about, even more so.

Exposure settings:

https://www.adobe.com/creativecloud/photography/hub/guides/camera-exposure-camera-settings.html

That article starts with the sentence '”Exposure” is how bright or dark a photo comes out', which is completely and utterly wrong. So, given that it starts out wrong, don't be surprised if just about everything in it is wrong.

Because when people think of "exposure", they think of the image.

That depends on who is 'people'. If 'people' is people who know what exposure is, they don't.

Your people have your definition of "exposure".

'My people', is the people who invented and defined the word 'exposure', either Hurter and Driffield or someone working around the same time. It includes every film manufacturer and also ISO. 'ISO' is defined in terms of exposure, so exposure cannot include exposure, by definition.

But you don't have a replacement for the exposure that includes ISO, which many other people are concerned with.

The word you're looking for is lightness. ISO determines the lightness that you get for a given exposure.

So shutter speed, aperture, and ISO are the settings for "lightness"?

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