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Zoom reach on crop sensors
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Jan 12, 2019 14:33:23   #
GoofyNewfie (a regular here)
 
Siemienczuk wrote:
One more question. I think I know the answer, but interested to hear other thoughts. My ability to handhold and obtain a reasonably sharp image is related to focal length and shutter speed. The longer the focal length, handheld, the quicker the shutter speed needed. For this question, ignore technique (stance, bracing) and use of image stabilization. A well known guideline is the reciprocal of the focal length. So if I’m using a FF sensor with lens 300 mm, a good benchmark is a shutter speed of 1/300 or faster. If I use a 300 mm lens with a DX sensor, does that reference change to 1/450 or is it still 1/300?
One more question. I think I know the answer, bu... (show quote)


You would have to apply the crop factor, so 1/450.
It’s just a rule of thumb from 35mm film days and before VR was a thing.
1/450 isn’t much different than 1/300, but if you had a camera with a very small sensor and used the reciprocal actual focal length, the shaking would show up pretty quickly.

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Jan 12, 2019 17:43:30   #
hassighedgehog (a regular here)
 
All longer lens crop the field of view no matter what camera is using it in comparison to, say, a 50 mm lens. The smaller sensor's just crop it more than a FF. Even film cameras worked that way. The apparent effect is greater magnification.

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Jan 12, 2019 20:02:51   #
nadelewitz (a regular here)
 
DebAnn wrote:
I understand that zoom lenses "reach" further on crop sensor cameras. Does a zoom lens specifically designed for a crop sensor camera have that effect? For instance, does a 55-250 mm zoom made for a crop have an effective reach of around 400 mm? Or does that only apply to lenses that work on both full frame and crop?


Your "understanding" is wrong. A lens does not "reach" further on a crop-sensor camera. The lens's focal length, or reach, DOES NOT CHANGE, EVER.
What is misinterpreted and misunderstood as longer "reach" is: on a crop-sensor camera, part of the lens's field of view is CROPPED off, so what you are seeing is what a longer-focal-length lens would see.

If you put a crop-sensor-intended lens on a full frame camera (you can do this on a Nikon but not on a Canon), it sees exactly the same field of view as ANY lens of the same focal length would see.

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Jan 12, 2019 21:11:18   #
Longshadow (a regular here)
 
nadelewitz wrote:
Your "understanding" is wrong. A lens does not "reach" further on a crop-sensor camera. The lens's focal length, or reach, DOES NOT CHANGE, EVER.

What is misinterpreted and misunderstood as longer "reach" is: on a crop-sensor camera, part of the lens's field of view is CROPPED off, so what you are seeing is what a longer-focal-length lens would see.

.....

The lens focal length itself does not change, the effect depends what camera you put it on.

Well, doesn't a longer-focal-length lens have more reach???

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Jan 12, 2019 21:31:51   #
frankraney (a regular here)
 
Siemienczuk wrote:
One more question. I think I know the answer, but interested to hear other thoughts. My ability to handhold and obtain a reasonably sharp image is related to focal length and shutter speed. The longer the focal length, handheld, the quicker the shutter speed needed. For this question, ignore technique (stance, bracing) and use of image stabilization. A well known guideline is the reciprocal of the focal length. So if I’m using a FF sensor with lens 300 mm, a good benchmark is a shutter speed of 1/300 or faster. If I use a 300 mm lens with a DX sensor, does that reference change to 1/450 or is it still 1/300?
One more question. I think I know the answer, bu... (show quote)


1/300.... A 300mm lens is a 300mm lens. Lenses are measured in mm, from the optical center to the sensor.

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Jan 12, 2019 21:36:59   #
GoofyNewfie (a regular here)
 
frankraney wrote:
1/300.... A 300mm lens is a 300mm lens.


True, but you still have to apply the crop factor if you’re going to use the reciprocal rule of thumb.

One can hand-hold medium format cameras for a longer shutter setting than with 35mm.

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Jan 12, 2019 21:45:35   #
DaveyDitzer
 
Linary wrote:
Any lens on a camera with a sensor smaller than full frame will produce a cropped image. On a Nikon AP-S camera body a 300mm lens will produce an image which has the same field of view of a 450mm lens on a full frame camera. This is not magnification, this is cropping.

This picture is worth more than a thousand words judging from the number of posts on this subject. Thank you!!

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Jan 12, 2019 21:46:51   #
frankraney (a regular here)
 
GoofyNewfie wrote:
You would have to apply the crop factor, so 1/450.
It’s just a rule of thumb from 35mm film days and before VR was a thing.
1/450 isn’t much different than 1/300, but if you had a camera with a very small sensor and used the reciprocal actual focal length, the shaking would show up pretty quickly.


Jim, Lens length does not change. A 300mm is a 300mm. So 1/300.... What changes the size of the image produced is the sensor....... Or have I been out in left field........

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Jan 12, 2019 21:59:25   #
frankraney (a regular here)
 
GoofyNewfie wrote:
True, but you still have to apply the crop factor if you’re going to use the reciprocal rule of thumb.

One can hand-hold medium format cameras for a longer shutter setting than with 35mm.


Jim, The lens length is 300mm, so why go to 1/450. The rules of this is 1/mm. The crop factor is only a comparison between a crop sensor and a ff sensor.....a 300mm on a crop sensor is like a 450 on a ff...or another way to put it, to take a shot with a ff 450mm and crop it down. A 300mm designed for a crop sensor is 300mm, and a 300mm on a ff is 300mm.

Am I all wet?

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Jan 12, 2019 22:13:51   #
GoofyNewfie (a regular here)
 
frankraney wrote:
Lens length does not change. A 300mm is a 300mm. So 1/300.... What changes the size of the image produced is the sensor....... Or have I been out in left field........


I never said it did change.

Look at it this way:
Let's say you shoot, hand held with VR off, the same subject with a medium format camera, a 35mm (AKA "full frame") and something with a 1" sensor, like the Sony RX10.
All from the same distance with lenses of equivalent focal length.

Aspect ratio differences aside, to get an 8 x 10 inch print (does anyone here ever print???) you would not have to enlarge the medium format image as much as a 35mm (FF). And the 35mm would not require as much enlargement as the SonyRX10 with the 1" sensor.
Enlarging the image always makes defects...artifacts...characteristics show up.
Camera motion would be a biggie.

The Sony RX 10 has 24-200 ff equivalent lens, but the actual focal length is 8.8-73.3 mm. (2.7 x crop factor if what I read is correct)
Unless you were a sniper, you'd never be able to hand hold that 200mm equivalent lens at 1/70th sec-- remember the actual focal length is 73.3mm-- and expect to get as sharp a result as a full-frame with a 200mm lens at 1/200th sec. It just isn't going to happen.

There is also pixel density to take into account with smaller sensors or even larger, higher-resolution sensors and a shorter shutter setting evidently helps there as well. I'm a photographer, not an enginerd so I leave that explanation for others who can explain that part.....ad infinitum as they often do here. (ZZzzzzz...)


More in these links:

What is Reciprocal Rule in Photography
"The basic premise of the reciprocal rule is that the shutter speed of your camera should be at least the reciprocal of the effective focal length of the lens."

Photography Basics - Reciprocal of Focal Length Shutter Speed Rule

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Jan 12, 2019 22:35:39   #
frankraney (a regular here)
 
GoofyNewfie wrote:
I never said it did change.

Look at it this way:
Let's say you shoot, hand held with VR off, the same subject with a medium format camera, 35mm (AKA "full frame") and something with a 1" sensor, like the Sony RX10.

Aspect ratio differences aside, to get an 8 x 10 inch print (does anyone here ever print???) you would not have to enlarge the medium format image as much as a 35mm (FF). And the 35mm would not require as much enlargement as the SonyRX10 with the 1" sensor.
Enlarging the image always makes defects...artifacts...characteristics show up.
Camera motion would be a biggie.

The Sony RX 10 has 24-200 ff equivalent lens, but the actual focal length is 8.8-73.3 mm. (2.7 x crop factor if what I read is correct)
Unless you were a sniper, you'd never be able to hand hold that 200mm equivalent lens at 1/70th sec- remember the actual focal length is 73.3mm and expect to get as sharp a result as a full-frame with a 200mm lens at 1/200th sec. It just isn't going to happen.

Evidently, there is also pixel density to take into account with smaller sensors and a shorter shutter setting helps there as well.
I'm a photographer, not an enginerd and I leave that explanation for others who can explain that part.


More in these links:

What is Reciprocal Rule in Photography
"The basic premise of the reciprocal rule is that the shutter speed of your camera should be at least the reciprocal of the effective focal length of the lens."

Photography Basics - Reciprocal of Focal Length Shutter Speed Rule
I never said it i did /i change. br br Look at ... (show quote)


Thanks Jim, for getting me or of left field.....I understand a lot of this but was not aware of using the crop factor in the 1/mm rule. I learned something today

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Jan 12, 2019 22:39:09   #
GoofyNewfie (a regular here)
 
frankraney wrote:
Thanks Jim, for getting me or of left field.....I understand a lot of this but was not aware of using the crop factor in the 1/mm rule. I learned something today

Hey, no worries!

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Jan 13, 2019 00:55:47   #
LWW (a regular here)
 
Linary wrote:
D500 is not a full frame camera.


They said D5000.

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Jan 13, 2019 04:02:30   #
Linary
 
LWW wrote:
They said D5000.


You are right, but that is also not a full frame camera.

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Jan 13, 2019 07:14:11   #
LWW (a regular here)
 
How is this topic so confusing to intelligent people?

YES a 300mm lens is still a 300mm lens whether it is attached to an APS or a FF body or a lamppost.

YES a 300mm lens does have more reach when attached to an APS body. On a FF body it is roughly 5X the reach of a “normal” lens or supposed human POV. When attached to an APS that reach becomes 9X.

YES with the front element still being the same size, the amount of light entering also remains the same so the f stop remains the same.

NO an APS sized sensor is not truly a “crop” sensor, it is merely shooting through the 2/3 sweet spot of the center of the lens.

If you use the same 300mm lens to shoot the same scene from the distance on both a FF and an APS sized sensor, to get the same FOV the FF image is the one that needs cropped.

Let’s say both sensors were 24 MP just of different sized sensors. The FF, to get the same FOV, would be cropped down to 16mm while the APS would maintain the full 24 MP.

It’s not magic, it’s science.

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