D7100: HOW MANY PIXELS AFTER CROP
Nov 14, 2015 17:36:32 #
This may be a very basice question. The D7100 has 24 Pixels, which is the reason I upgraded from a D300 (12 Pixels)
In the Camera you can set the Image Area a full 24mm x 16mm, or for a Cropped area, 18mm x 12mm. I understand the cropped area results as a closer in image (I basically shoot wildlife so that can be important). When you use the Crop Image Area I understand that you will loose some of the 24 Pixels. Question? Since you have a smaller image, does the decrease in Pixels really change in the, so-to-speak, Pixels per mm? Thanks for any help in making me understand this. I have been reluctant to use the Crop Image Area for fear of loosing resolution, Pixels.
In the Camera you can set the Image Area a full 24mm x 16mm, or for a Cropped area, 18mm x 12mm. I understand the cropped area results as a closer in image (I basically shoot wildlife so that can be important). When you use the Crop Image Area I understand that you will loose some of the 24 Pixels. Question? Since you have a smaller image, does the decrease in Pixels really change in the, so-to-speak, Pixels per mm? Thanks for any help in making me understand this. I have been reluctant to use the Crop Image Area for fear of loosing resolution, Pixels.
Nov 14, 2015 17:47:09 #
1046William wrote:
This may be a very basice question. The D7100 has... (show quote)
The D7100 sensor is 23.5mm x 15.6mm in size and has 6000 horizontal pixels and 4000 vertical pixels giving you 24 MEGA pixels of image. This means you will have approx. 256 pixels per mm of image width or height. Simply multiply the desired mm size by 256 to determine MP size. (18x256=4608, 12x256=3072, so 4608x3072=14.15MP of image remaining after the crop.)
Nov 14, 2015 18:30:27 #
1046William wrote:
... I understand the cropped area results as a closer in image (I basically shoot wildlife so that can be important). ... I have been reluctant to use the Crop Image Area for fear of loosing resolution
... I understand the cropped area results as a closer in image (I basically shoot wildlife so that can be important). ... I have been reluctant to use the Crop Image Area for fear of loosing resolution
Shoot with all your pixels, and then if you wish to crop, do so after-the-fact, in post-processing. You may change your mind about how you want the image to look + you'll always have your original.
If you haven't done much editing, there are several free programs. One I like is Picasa, by Google. The crop tool is very easy to use.
Here is the link:
http://picasa.google.com
Nov 14, 2015 18:53:45 #
Low Lids
Loc: Gainesville, Florida
Carter, Thanks for that explanation! One question, using the D7100 (and shooting the same subject, same lens, same focal length, same 'subject-to-camera-distance) as long as the subject (a bird) doesn't exceed the borders of the cropped image area, there is no image resolution lost whether taken in DX or in cropped image selection. It just appears larger in the cropped finder area, correct?
I'm considering that even though the cropped image area is smaller, the bird takes up a greater portion of that area.
I'm still at a loss as to how Nikon's 1.33X crop factor relates to the difference between the two areas? Dividing 24MP by the crop factor of 1.3 equals about 18MP. The calculated size of the cropped area equals about 14MP. Where did Nikon come up with the 1.3x crop factor?
I'm considering that even though the cropped image area is smaller, the bird takes up a greater portion of that area.
I'm still at a loss as to how Nikon's 1.33X crop factor relates to the difference between the two areas? Dividing 24MP by the crop factor of 1.3 equals about 18MP. The calculated size of the cropped area equals about 14MP. Where did Nikon come up with the 1.3x crop factor?
Nov 14, 2015 20:06:21 #
Low Lids wrote:
Carter, Thanks for that explanation! One question,... (show quote)
The 1.3X crop feature of the D7100/7200 body reduces the sensor size to the same format as the 4/3's sensors giving the user a net 2X crop factor overall. This will give your crop sensor camera using a 400mm lens the equivalent field of view as an 800mm lens on a full frame body. But it's STILL cropping, and ANY cropping is nothing more than discarding pixels, in camera or in PP software.
Nov 14, 2015 21:03:03 #
I do have experience at processing. I realize, as Shooter stated, that when you crop you go from 24 MP to 18 MP. My question was in the cropped area are the MP that remain at the same concentration, just less of them in a smaller area?
Nov 15, 2015 05:26:34 #
mikegreenwald
Loc: Illinois
Within the cropped area no pixels are lost. However when any enlargement of the cropped area occurs, the concentration of pixels (pixel density) is lower than it would have been in an uncropped picture of the same size.
Nov 15, 2015 07:07:04 #
William, the math can be confusing... drawing on teaching high-school.... Sex and Food are the keystone of understanding and teaching with out using math!! Only food is "school appropriate."
So, here goes with food: If you shoot a slice of bread and it has a certain thickness of peanut butter** per sq inch and you slice and end up with a 2" sq of the bread that is cropped but contains the starting thickness of peanutbutter per sq inch.
Now if you take off the peanut butter from that 2 sq inches and put on another full slice the amount of peanut butter per sq inch is much less.
Same applies when you do an 8x10 of a not cropped image vs an 8x10 of a small section of that out of camera image... the pixels are spread out ... thus much fewer pixels per sq inch of image. Eventually if thin enough you see the pixels because they cover a wide area each. Pixelation. see:
https://en.wikipedia.org/wiki/Pixelation
**adding jelly would complicate the discussion
So, here goes with food: If you shoot a slice of bread and it has a certain thickness of peanut butter** per sq inch and you slice and end up with a 2" sq of the bread that is cropped but contains the starting thickness of peanutbutter per sq inch.
Now if you take off the peanut butter from that 2 sq inches and put on another full slice the amount of peanut butter per sq inch is much less.
Same applies when you do an 8x10 of a not cropped image vs an 8x10 of a small section of that out of camera image... the pixels are spread out ... thus much fewer pixels per sq inch of image. Eventually if thin enough you see the pixels because they cover a wide area each. Pixelation. see:
https://en.wikipedia.org/wiki/Pixelation
**adding jelly would complicate the discussion
Nov 15, 2015 07:18:20 #
Like the others said, Do your cropping in PP. The only time I ever use the crop function on the D7100 is when I want to extend my burst shooting because of the small buffer of the camera. Even then, I only do that when I want to remain in RAW because you can get more out of the buffer by changing to jpeg than by using the cropped frame setting
Nov 15, 2015 07:41:11 #
If the pixel count gets too low... look into upsizing using programs contained within your editor... and if really pushing then use an expensive program like OnOne true fractal or a bargain of an older Benvista program sold by Ashampoo.
https://www.ashampoo.com/uk/usd/pin/fremd032/partner-software/PhotoZoom-Classic-5
Reduced to $20 (if it comes up with my charge card... change it to yours please... yep it happened once!!)
Both the OnOne and Photozoom claim upsizing approaching 1000X while others in editors or Faststone Resize work well for smaller increases perhaps X10.
https://www.ashampoo.com/uk/usd/pin/fremd032/partner-software/PhotoZoom-Classic-5
Reduced to $20 (if it comes up with my charge card... change it to yours please... yep it happened once!!)
Both the OnOne and Photozoom claim upsizing approaching 1000X while others in editors or Faststone Resize work well for smaller increases perhaps X10.
Nov 15, 2015 08:59:35 #
Nov 15, 2015 09:34:44 #
dpullum wrote:
William, the math can be confusing... drawing on t... (show quote)
You explanation is absolutely great, very understandable.
Nov 15, 2015 09:57:07 #
londonfire
Loc: NY to NC
Reduced to $20 (if it comes up with my charge card... change it to yours please... yep it happened once!!)
Hi, dp. I tried that link and it comes up at $69. Am I doing something wrong? Thx...
Hi, dp. I tried that link and it comes up at $69. Am I doing something wrong? Thx...
Nov 15, 2015 11:01:52 #
For those interested my wife is doing a couple of calendars at Adorama. On their site the have a great chart for dpi, ppi and size of photos.
Small shop but love going in. Some days B & H is just too big.
Small shop but love going in. Some days B & H is just too big.
Nov 15, 2015 11:18:22 #
londonfire wrote:
Reduced to $20 (if it comes up with my charge card... change it to yours please... yep it happened once!!)
Hi, dp. I tried that link and it comes up at $69. Am I doing something wrong? Thx...
Hi, dp. I tried that link and it comes up at $69. Am I doing something wrong? Thx...
YES.... subscribe to Ashampoo...
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when you are a member... then you are part of "the ashampoo loyal people."
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