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D700, it's official. (1 Viewer)
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Gentoo
Guest
I'd have to agree. As birders, we shoot in the telephoto which the D300's DX sensor in some ways is an advantage. The zoom and crop factor gives us just a bit more reach. The only thing that the full size sensor would give us is better ISO performance but does anyone every shoot at 3200 or 6400?
Gentoo
Guest
If you compare picture quality side by side with the D3 and D300 using the same lens and camera setting, I bet you'd be hard pressed to pick them out.
Dipper
Well-known member
Will an FX sensor be better for macro photography than a DX? I think it will give better dof than the DX especially with the 105VR.
Adi
http://www.flickr.com/photos/46984194@N00/
Adi
http://www.flickr.com/photos/46984194@N00/
Tricky question. They are both the same. BUT. Lets say you frame a shot with the DX camera and to get the size in the frame you require you zoom to 50mm. With an FX sensor to get the same shot you will need 75mm. Now the depth of field is related to the focal length (greater focal length = less DOF).
It's the opposite! |=)|
Basically the DOF is a function of aperture, image magnification and circle of confusion. Now it so happens that the first two are the key parameters. So as you increase the magnification at a given F ratio, so the DOF reduces. That is why a DX sensor gives about 1 extra stop of DOF at a given F number and composition. You have to realise here that we are talking about similar compositions. So for a given subject, using the FX camera you move nearer to get the same framing.
Dave Williams
Well-known member
Interesting article. I think it supports the theory that for bird photography the D300 is a better option.
Am I right ? If so thank goodness, yearning for a longer lens is bad enough without having to wish for the more expensive body too.:smoke:
DOF is independent of focal length. Unless you are standing at the same spot, and change lenses, with the same F number. And that is because the image magnification changes.
Having had a peek at that article, by someone who is as you say respected, I must admit that his claims do not match my experience. I use micro lenses for insects and fungi, and I find that stopping down from F8 to F11, or even F16, gives a very noticeable and significant increase in DOF, which is to be expected from the maths. Whereas BR claims insignificant change in DOF associated with a 1 stop difference in the F number.
In practice it does matter a lot. Trying to align the sensor plane with a damselfly is very hard, especially in dull light, and using a smaller aperture (larger F number) leads to more keepers. To bring this down to Earth, here is the sort of thing I am talking about:
http://gallery.photo.net/photo/6572152-lg.jpg
And why does the magnification change? Because you change the focal length. Focal length is a major factor in the DOF calculation. Look at any online DOF calculators.
No need to buy a new camera. He does indeed say for many resons the D300 is better for birds unless you need better tracking and higher ISO ratings.
I have looked at DOF calculators.
DOF is better expressed in terms of image magnification and not focal length. That is because if I take a portrait of you with 50mm and 100mm lenses, I do not stay in the same place. I normally move to get the same framing. I use 60mm, 105mm and 200mm micro lenses, and they have the same DOF givne the same subject framing. In other words, if I use one of them to photograph a dragonfly, the DOF is a function of the aperture and the image size only. What does change is the FOV, and working distance, which are the key features.
I made no such claim. And I have done plenty of research, and routinely see the effect of changing the aperture on the DOF, and I know how significant it is in practice i.e. in the field.
It is easy to be an armchair expert using online articles written by others.
Dipper
Well-known member
All things being equal, the same aperture setting, iso, distance, lens etc just a change of format from DX to FX then I would expect greater dof with an FX. For example using the 105VR on a D200 would actually be a 157.5mm because of the 1.5 multiplying whereas on an FX D700 the 105VR would be a 105VR and I would expect the dof to be greater. No moving, no reframing, no lens changes. Does that make sense? Or is it all wrong?
Adi
http://www.flickr.com/photos/46984194@N00/
Adi
http://www.flickr.com/photos/46984194@N00/
I use a D200, thought that would be little different from a D300. I routinely see the effect of different apertures, as most weekends I am out taking photos of insects, plants etc. I respect Rorslett's technical ability, though I found that article somewhat conceited, as he effectively says "everyone online is talking nonsense, and so here is the truth", and I found his conclusions on the effect of aperture on DOF hard to square with my own observations.
You only have to do the maths to see effect of F stop on DOF.
If you do not move, and you use the same aperture and lens, then the DOF is the same. Think about it. The DX camera will register an image that is simply a crop of the one registered by the FX sensor. (Well, pixel density will differ.)
The 105mm lens is always 105mm, irrespective of the sensor. I suspect you are confused by the tendency to talk about a 105mm lens 'transforming' into ~150mm on DX. Well, it doesn't, but it will have a reduced FOV, equivalent to that of a ~150mm lens on FX.
