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Author Topic: Using a FX Camera in DX Mode  (Read 316 times)

Mark Nadler

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Using a FX Camera in DX Mode
« on: March 24, 2019, 11:18:52 am »

I am using a Nikon 850 with a Nikon 200-500 lens.  I use this combo to shoot birds and to shoot
closeups (from a distance) of insects, butterflies etc.  Often when I take pictures of birds I end up
cropping much of the original image.  So here's my question: if I shoot my camera in DX mode and thus
extend "the power" of my lens and by implication produce images that require less cropping will I
potentially create more images that in fact have more megapixels in them than when shooting in FX mode?

Thanks.

Mark

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Two23

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Re: Using a FX Camera in DX Mode
« Reply #1 on: March 24, 2019, 01:37:15 pm »

No.  I shoot many different formats including 4x5, 5x7, 6x9, and so on.  A crop is a crop.


Kent in SD
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Mark Nadler

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Re: Using a FX Camera in DX Mode
« Reply #2 on: March 24, 2019, 01:50:20 pm »

So, Kent or anyone else, if I might ask you an additional question: ignoring issues like price and weight and size why would anyone buy a DX
camera?  I keep reading that the benefit of a DX camera for wildlife photography is the additional reach it gives you.  If the additional
reach does not translate into more megapixels in a finished image then why bother?  Why not just shoot FX and crop into the image you
want.  I hope I am not being hopelessly confused.

Mark
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Telecaster

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Re: Using a FX Camera in DX Mode
« Reply #3 on: March 24, 2019, 05:45:20 pm »

The current DX sensors give you greater pixel density than the FX ones. A Nikon D850 image cropped to DX size has a bit over 19mp, compared to 24mp with the latest DX chips. Not a big deal if you only occasionally crop, but if maximizing the number of pixels devoted to your wildlife subjects is important then the DX sensors have an advantage.

-Dave-
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Two23

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Re: Using a FX Camera in DX Mode
« Reply #4 on: March 24, 2019, 09:36:35 pm »

So, Kent or anyone else, if I might ask you an additional question: ignoring issues like price and weight and size why would anyone buy a DX
camera?  I keep reading that the benefit of a DX camera for wildlife photography is the additional reach it gives you.  If the additional
reach does not translate into more megapixels in a finished image then why bother?  Why not just shoot FX and crop into the image you
want.  I hope I am not being hopelessly confused.

Mark


I own and use a D500.  Main reason is cost.  I bought it for $1,000; a used D850 is going for $2.500.  The performance of the D500 is fantastic.  I use it for sports, wildlife, etc.  I use the Nikon D800E for night shots, architecture (with 24mm PC-E), and landscapes.  I'm planning on buying a used D850 when they start hitting $2,000 on the used market but will keep the D500. It's smaller & lighter, and I do want a back up camera that uses Nikon mount.  Lately I've mostly been shooting winter scenes with my Chamonix 4x5 and black & white film.  Haven't touched the D800E in over a month. :)


Kent in SD
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Dan Wells

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Re: Using a FX Camera in DX Mode
« Reply #5 on: March 25, 2019, 11:18:07 am »

The D850 (and Z7) come (as Telecaster noted) relatively close to DX  pixel density, but nothing else in Nikon's line does... On the Canon side, the 5Ds/5DsR used in crop mode are close to Canon APS-C cameras, and for Sony, the A7rII and A7rIII are close to Sony's APS-C line. Any other full-frame camera will have many fewer pixels when cropped than a dedicated APS-C camera. The few 36 MP cameras (D800, D800e, D810, original A7r and Pentax K1 series) crop to about 15 MP, the 30 MP Canon 5D mkIV crops to about 12-13 MP, and everything else crops to around 10 MP.

Of the FF cameras with enough resolution to serve as viable crop cameras (assuming you aren't willing to live with 10 MP images), there is one in particular that stands out. The D850 is a very quick camera that speeds up even more in crop mode, and it has an AF system that works very well with long lenses. If you have a D850,  the only real reasons to also own a crop body are if the last few pixels matter to you (D850 crops to 19 MP, D7500 is 24 MP - but note that the D7500 is not as capable a body as the D850 in terms of focus or durability - the very capable D500 is almost exactly the same resolution as a cropped D850) OR if you want a second body anyway, can't afford a second D850 (again, or a Z7) and shoot enough wildlife that you'd rather have the crop performance of a D500 than something like a D750.

If your FF body is a Z7 or one of the Sonys, you might well use it in crop mode. A Z7 with a long lens on the FTZ will outperform any Nikon crop body except the D500. The rest of the lineup are consumer-grade cameras that won't match the performance of a Z7, but a D500 will significantly exceed it. Z7 and D500 are a very interesting pair, because each has strengths where the other is weaker. The Sonys, especially the A7rIII, are very good performers, and Sony doesn't really have a tempting high-end crop body to pair with it (although there are a lot of rumors).

The Canons are really not viable crop choices for other than occasional use. The 5Ds series are slower than you'd want for wildlife or other
crop-friendly subjects, and Canon has a couple of quick APS-C bodies that are much better choices. Of course, if you happen to be holding a 5DsR with a 600mm lens on it, and a great bird photo presents itself, it'll work just fine. It's just not the camera of choice if that's what you're after most of the time.
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