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OK Digital zooming one more time


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Going back to Nicci's post - the f-stop are DOF equivalence when using F1.7 (haven't verified actual numbers, just copy and pasted)

28mm = 47.3 MP f/1.7

35mm = 30.3 MP f/2.1

50mm = 14.8 MP f/2.55 

75mm =   6.6 MP f/4.55

Edited by dancook
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47 minutes ago, douglas fry said:

Actually reading Jono's review more thoroughly, I see that you DON'T get a 75mm lens in real terms on a Q2 body, its everything a 75mm lens would ebe on a cropped sensor, so the depth of field is greater at the same aperture.

 

 

I do not think you have got that right. It would be a 75 mm equivalent lens on a cropped sensor, so for instance 37.5 mm on an MFT sensor.

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9 hours ago, douglas fry said:

if I stand still, and photograph a car, and shoot at 28mm and then zoom to 75mm and shoot again, the crops will be the same as the perspective is identical in both instances, no? So do you get a 'free' 75mm lens in all aspects with the Q (other than pixels)?

If you do not move at all and switch from a 75mm crop Q2 to another camera with 75mm lens or equivalent. You will get the same type of image with the same perspective, because distance did not change. But depth of field can be different, it depends from equivalent aperture 

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8 hours ago, dancook said:

Going back to Nicci's post - the f-stop are DOF equivalence when using F1.7 (haven't verified actual numbers, just copy and pasted)

28mm = 47.3 MP f/1.7

35mm = 30.3 MP f/2.1

50mm = 14.8 MP f/2.55 

75mm =   6.6 MP f/4.55

The maths are really easy.  

Just divide the crop 35 50 or 75 by 28 to get the crop factor (it will gives you the sensor size equivalent) 

then multiple the crop factor by 1.7 aperture to get equivalent aperture for depth of field. 

Aperture and exposure will stay a true f/1.7 whatever the crop chosen ! 

For pixel counts, just divide 47.3 MP by the crop factor squared. 

So you get :

35mm = 1.25x crop factor bigger than M8 APS-H sensor

50mm = 1.79x bigger than m4/3

75mm = 2.68x equal to 1“ sensor

Edited by nicci78
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sadly 50mm and especially 75mm framelines are too small to be really useful. How to be sure of what we are shooting with such a small image. 

However 35mm lines are perfect, with enough out of field for better composition. 

Q2 acts as an analog MP/M7/M6 with 0.58x viewfinder. Very nice with 35mm lenses, but very small with 50 and 75mm ones. 

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Which is exactly why I rarely use the built in crop.  I shoot DNG and process every image.  Picking my crop in post doesn't add but a few seconds and lets me get exactly the crop I'm looking for.   Even if I do crop to a 35mm or 50mm equivalent rarely do I want the exact middle of the shot to fill my crop.

If I were shooting jpegs to instant upload to social media I'd probably feel different.

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When you crop to a longer focal length equivalent, you lose the compression and the depth of field you would get when shooting at that longer focal length.

IMO, the usability then depends on what your subject matter is.  For street photography you might like it because the wider depth of depth works to your advantage.  

For portraits, on the other hand, the difference will be noticeable, because you want the shallower depth of field and the compression, and better subject isolation.

Also, keep in mind that once you crop your image from Q2 to a 75MP equivalent, noise in your image will be more noticeable, and the perceived sharpness will drop.  

Edited by xaradaisy
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3 hours ago, xaradaisy said:

When you crop to a longer focal length equivalent, you lose the compression and the depth of field you would get when shooting at that longer focal length. [... snip because double fishing hooks are illegal ...]

Oh boy, here we go again. Did he write that to make us feel really young again? Dude, what's your rotary phone dial-up  speed?

Edited by pico
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4 hours ago, marchyman said:

Which is exactly why I rarely use the built in crop.  I shoot DNG and process every image.  Picking my crop in post doesn't add but a few seconds and lets me get exactly the crop I'm looking for.   Even if I do crop to a 35mm or 50mm equivalent rarely do I want the exact middle of the shot to fill my crop.

Precisely.

Which is why I think this whole in camera cropping function that Leica tries to sell is a gimmick in a way.

You have more control over your cropping during editing, and like you said, does not take too much of extra time at all.

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Am 8.3.2019 um 21:09 schrieb nicci78:

The maths are really easy.  

Just divide the crop 35 50 or 75 by 28 to get the crop factor (it will gives you the sensor size equivalent) 

then multiple the crop factor by 1.7 aperture to get equivalent aperture for depth of field. 

Aperture and exposure will stay a true f/1.7 whatever the crop chosen ! 

For pixel counts, just divide 47.3 MP by the crop factor squared. 

So you get :

35mm = 1.25x crop factor bigger than M8 APS-H sensor

50mm = 1.79x bigger than m4/3

75mm = 2.68x equal to 1“ sensor

Do not forget to take the ISO into the maths. We have 3 variables that affect the picture when cropping or changing sensor size: Focal length, Aperture and ISO. For no moving subjects the shutter speed has no influence on the image quality.

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On 3/8/2019 at 11:21 AM, dancook said:

Going back to Nicci's post - the f-stop are DOF equivalence when using F1.7 (haven't verified actual numbers, just copy and pasted)

28mm = 47.3 MP f/1.7

35mm = 30.3 MP f/2.1

50mm = 14.8 MP f/2.55 

75mm =   6.6 MP f/4.55

The 50mm should be   14.8MP f/3.0

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Am 8.3.2019 um 12:21 schrieb dancook:

Going back to Nicci's post - the f-stop are DOF equivalence when using F1.7 (haven't verified actual numbers, just copy and pasted)

28mm = 47.3 MP f/1.7

35mm = 30.3 MP f/2.1

50mm = 14.8 MP f/2.55 

75mm =   6.6 MP f/4.55

so we have:

Summilux 28mm

Summicron 35mm

Summarit 50mm

not bad in my opinion :)

 

PS: I have the Q2 and I can just say: its the best :)

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Am 8.3.2019 um 21:15 schrieb nicci78:

sadly 50mm and especially 75mm framelines are too small to be really useful. How to be sure of what we are shooting with such a small image. 

 

its the same with the M10 - 50mm framelines?

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9 hours ago, Alex U. said:

Do not forget to take the ISO into the maths. We have 3 variables that affect the picture when cropping or changing sensor size: Focal length, Aperture and ISO. For no moving subjects the shutter speed has no influence on the image quality.

That might require clarification. For example, shutter speed to make, for example a 75mm from full-frame should be raised if the print or presentation is the same size as an an uncropped image because while the subject is not moving, the camera might be. (If one has a heartbeat there is camera motion.)

 

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