We are. You're referring to resolution.
DX Mode
- Thread starter Bear Dale
- Start date
We are. You're referring to resolution.
Horoscope Fish
Senior Member
You can listen to those bone heads on DP Review if you so choose, but @480sparky is absolutely correct. Crop Factor relates to sensor size. Period. Pixel Density is an entirely different topic and trying to compare the two is akin to comparing meatloaf to butterflies.
The people at B&H Photo Video have one of the best explanations on this topic I've found: Understanding Crop Factor. If you read the entire article from top to bottom you'll notice it never mentions pixel density. Not. Even. Once. Why? Because Pixel Density has absolutely NOTHING to do with Crop Factor. The people DP Review can talk about "pixels on the duck" all they want, they can call it whatever they want, call it pan-seared filet mignon if that's what does it for you but the facts remain the same: Crop Factor is tied to sensor-size, and Crop Factor and Pixel Density are two unrelated things.
Now, should you decide to dispute things in light of this article I wish you fair winds and following seas!
Fine. Crop factor is related to sensor size. It gives you a different FOV. I think everyone can agree on that. Maybe the OP will chime in, but I think he was asking about reach. That's where pixel density comes in. Pixel density is one huge reason why wildlife photogs use DX cameras. The end result is that I can get shots on my D500 with a 500mm lens that would require a 750mm lens on an FX camera (except in the case of the D850 because it nearly matches the pixel density).
They say a picture says a thousand words, so here is a demo. I just took these shots through my back window (forgive the quality). First are the full-frame shots from a D750 (top) and a D500 (second from top). As you can see, the crop sensor on the D500 is simply giving me a cropped version of the D750 shot. Next are 100% crops. The D500 crop is surely giving me what I'd call more reach. Why is that? It's because the pixel density is much higher than that of the D750. If this isn't clear enough, then I'm afraid that's all the explaining I can do. In a wildlife situation where we can only get so close to the subject, the camera with the higher pixel density is king, and the extra "reach" it gives is a very real thing.
You are explaining it just fine. We all get it. But it's not what 99.999999999% of us consider 'reach'. We call it resolution.
Horoscope Fish
Senior Member
The only difference I see in your photos is the subject (the transformer, the sign ON the transformer) is more frame-filling on shots where the crop-sensor was used.
That the subject is more frame filling (all other things being equal), as compared to how frame-filling the same shot is compared to the full-frame sensor is, to me, getting more "reach". If you care to explain your definition of "reach", I'm all ears.
More importantly I, or anyone else, could duplicate those results using ANY full-frame sensor camera compared to ANY crop-sensor (1.5x crop factor assumed) camera because the crop factor, which results in more "reach", or more of the frame being filled with the subject (all other things being equal), is tied to the size of the sensor.
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I suppose my definition of reach is—a larger final image. Imagine that sign on the transformer were a bird. If the distance I shot it from is the closest I can get, the bird is going to be bigger in the DX image. Also, because the pixel density is higher, there's going to be a lot more detail. Look at how much clearer the D500 crop is.
Here are the two crops again. This time, I cropped the D750 image to give (roughly) the same framing as the D500 crop. The final D750 crop is only 0.34 MP, while the D500 crop is 0.77 MP. This is what I call more reach. Unfortunately, I don't think you can duplicate that with any full frame camera. You'd have to have a FF camera that matched the px density of the D500. Now, you could enlarge the D750 crop so it's the same MP as the D500 crop, but that's just going to make it look even blurrier. This is why I shoot a D500 when I need "reach."
Horoscope Fish
Senior Member
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Not sure what your point is. I pulled down and opened two of your images; on the left is one of your shots from the D500. On the right is the same shot, so to speak, but taken with the D750. Image file names display in the top left corner of each.
Image size for both shots is 600 x 400 pixels and both are being viewed at 100% magnification as you can see at the bottom of each shot:
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Horoscope Fish
Senior Member
Which is pretty much how we all define "reach" when referring to crop factor, zoom lenses, etc.
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Which is due to the higher resolution.
I know I'm essentially repeating 480sparky's previous post but there are only so many ways one can put this.
I don't know about those cameras, I'm talking about digital camera sensors with pixels.
I'm not sure what we're fussing about here. The advantage of higher px density is very real. How about instead of calling it reach, we call it the "pixel density advantage." See this:
An analysis of the pixel size of the 36mp full frame Nikon D800 compared with the pixel size of the 24 mp APS-C Nikon D3200). Crop factor of Nikon D3200. Pixel size of Nikon D800 vs pixel size of Nikon D3200
When comparing an FX camera to a DX camera, and the DX camera has a higher px density, it has a distinct advantage. Simply cropping a DX shot out of the center of the FX frame will give a smaller and blurrier image. What's nice about the D850 is that it nearly matches the px density of the D500, so you can crop out the center and get the same thing. I think this is what the OP was asking. Yes, you can put the D850 in DX mode and it should give nearly the same results as using a DX camera like the D500. You end up with a 19.4MP image vs 21 MP from the D500.
An excerpt from the above article:
Crop an image from D800 to the same field of view as an image from D3200
Gain in image width (in pixels) as a result of the above 25.5% pixel density advantage
Uncropped image width of D3200 = 6016 pixels
Cropped image width of D800
to same field of view as D3200 = 4756 pixels (7360 x 23.2 / 35.9)
Relationship: D3200 is approximately 26.5% greater than D800.
And that, in my book , is more reach.
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Call it a ham sandwich for all I care. I'll just stick with resolution. It's a term others know and understand well enough.
There are many factors that come into play. It's not just sensor size, or just resolution or just pixel density. In the examples I posted earlier, the D750 actually has higher resolution (to start with), but the cropped image is smaller and blurrier. In that example, the D750 cannot match the D500 simply by cropping. The photographer has to either get closer, or use a 750mm lens.
To me, reach is about how easily I can fill the frame. It's way easier to fill the DX frame when you're limited by focal length. Plus, because of the pixel density, I can crop down from there if needed, and still have a nice image.
If the OP has a D850, it shouldn't matter whether he shoots it full frame and crops later, or just shoots in DX mode to begin with. With cameras like the D810 and D750, DX mode is inferior to just using a DX camera from the get go.
Bikerbrent
Senior Member
Frankly my dear, who gives a damn!
TL Robinson
Senior Member
Couple examples of the D750 shooting in DX mode using the Sigma 50-100mm Art lens:
750_6136 by Tim Robinson, on Flickr
750_6154 by Tim Robinson, on Flickr
750_6161 by Tim Robinson, on Flickr
750_6136 by Tim Robinson, on Flickr
750_6154 by Tim Robinson, on Flickr
750_6161 by Tim Robinson, on Flickr