Crop factor

merv

merv

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Mervyn
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This crop factor issue is causing me a bit of grief in trying to come to terms with it. I have a DX D300 and FX D700. I plan to go shooting rally cars at the weekend and dont know which camera to use with my 300/2.8 and 70-200 lenses. I do appreciate about angles of view, but what is the right choice to make. Apparently a 300 focal length is just that on both cameras but the angles of view are different so how does that affect the end result. Please explain. Thanks merv:thinking::thinking:
 
On DX multiply focal length by x1.5 so 300mm = 450mm FoV

200mm lens on DX equates to 300mm FoV so the same as the 300mm on FXid whack the 70-200 on the D300 and the 300mm prime on the D700, effectively giving you the dame FoV in both bodies.
 
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Shooting on the DX is the same as shooting on the FX then cropping. As both are 12Mp cameras, the FX image will therefore be smaller.
 
EOS_JD said:
Shooting on the DX is the same as shooting on the FX then cropping. As both are 12Mp cameras, the FX image will therefore be smaller.
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In this situation, while shooting with the D700 in crop mode would give the the same field of view in the image as shooting with the D300, the D700 would be a 5mp image, and the D300 would be 12mp image.
 
Yes REdhead, so if my D300 shot with the 300 lens fills the frame, to get the frame filled with the same lens on the D700 I will have to crop the full frame image resulting in an image with a file size of 5Mp. Have I got that correct? So if I can fill the frame with the 300 lens on the D700 go ahead and use the FF camera. However, if I am too far away to fill the frame, use the D300 to get a higher quality image that does fill the frame ie 12Mp. Obviously the 5Mp image doesnt make enlarging so easy as the resolution will be considerably lower. Hope I've got that right! Thanks merv:thinking:
 
redhed17 said:
In this situation, while shooting with the D700 in crop mode would give the the same field of view in the image as shooting with the D300, the D700 would be a 5mp image, and the D300 would be 12mp image.
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Yes - which is exactlyt the same as cropping in Ps - Although if using the D799 I'd prefer to shoot at FF just in case I needed the extra - I don't get the DX format in a FF camera (other than to save time cropping)?
 
merv said:
Yes REdhead, so if my D300 shot with the 300 lens fills the frame, to get the frame filled with the same lens on the D700 I will have to crop the full frame image resulting in an image with a file size of 5Mp. Have I got that correct? So if I can fill the frame with the 300 lens on the D700 go ahead and use the FF camera. However, if I am too far away to fill the frame, use the D300 to get a higher quality image that does fill the frame ie 12Mp. Obviously the 5Mp image doesnt make enlarging so easy as the resolution will be considerably lower. Hope I've got that right! Thanks merv:thinking:
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5Mp is still pleanty big enough for a decent sized print - How big do you expect to print?
 
Normally A4 but sometimes for competitions A3. Thanks for your help guys. merv:clap:
 
This got it straight in my head.

Outside white line is full frame, inside white line is cropped.

It's not zoomed in any closer, it is just literally a crop of the full frame version.

To obtain the same frame on a full frame you would have to zoom - I think that's where the confusion come in.

crop_image_01.jpg
 
Yes Barry that is very clear. Basically my dilemma is as follows. I have a D300 and D700 and shoot motorsports and landscapes etc. I have always looked on the D300 as the one for sports, air shows etc and D700 for the rest. What I want to know is there any advantage in using the FF for motorsports. The lenses I tend to use are 70-200 and 300 prime for sports but could also use these on the D700. thanks merv:bang:
 
BarryG said:
This got it straight in my head.

Outside white line is full frame, inside white line is cropped.

It's not zoomed in any closer, it is just literally a crop of the full frame version.

To obtain the same frame on a full frame you would have to zoom - I think that's where the confusion come in.
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Surely the outside white line is the APS-C Sensor (crop) and the inner line is FF ?? For a given focal length of lens, the crop sensor camera will always show a larger image (that's why a 200mm lens "behaves" live a 250/260mm lens on a crop body).

Edit: Ignore that, I've been on the stupid pills this morning !!!

Steve
 
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The main benefit of full frame is image quality - better sharpness (it's not just about pixels), more dynamic range, less noise. Because the sensor is more than twice the size and collects far more photons - the basic building material, more to work with - and doesn't work the lenses so hard so contrast is higher for a given standard of resolution.

The downside of that is cost, plus when it comes to longer lenses you need bigger lenses (and much more costly ones) to obtain the reach. Another side effect is that depth of field is affected for an image framed the same, because of the focal length and magnification changes needed to restore the same field of view. The difference is that you get just over one stop more DoF with crop format f/number for f/number, ie f/4 on a cropper gives the same DoF as f/6 on FF. That's about 1.2 stops on a Nikon, the formula is f/number x crop factor.

Since you have a D700, if you can get enough reach using that, then that's the obvious choice.
 
Thanks Hoppy. Jelster where did you say you got those pills? merv:lol:
 
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