Category Archives: D7100

equivalence is more equal than you think

There is a perpetual online discussion amongst measurbators about “equivalence”.

 

Equivalence is a very real phenomenon which can be predicted and measured.  The idea is that when comparing cameras with different sensor sizes, smaller sensors tend to have greater depth of field at “equivalent” focal lengths.

 

Why “equivalent” focal lengths?  Ok, it gets technical pretty quick, but rather than bore you with esoteric technobabble, lets just look at some images.  (Photography is about making images, right?!)  If you feel that the differences are drastic, then by all means read on.  But if none of these images strike you as dramatically different from one another, just know that you can safely ignore anybody who ever mentions “equivalence” or “equivalent apertures”.  Because they’re either trying to waste your time or sell you something.  (hopefully I’ll have saved you from the clutches of some forum troll)

 

Here they are:

MG1_0730

MG2_3230

P1060916

This is what the war is about.  A mountain of a mole hill, idn’t it?

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Is your lens busted?

I’ve just had my first absolutely awesome experience with the Nikon USA repair department (all previous ones having been abysmal). They did a bang up job (for a price!) of bringing my many times dropped 70-200mm VR (V1.0) lens back to spec. And the proof is in the images!

 

This was shot with the 70-200mm, a TC14E, and a crappy Tamron 2x extender, on a D7100 (for a grand total of 840mm equivalent in 35mm) and it STILL looks good (in my opinion)

 

I’ve never personally sent a lens in for repair to Nikon–only bodies. And we all know how bad that went!

 

So with my first decent Nikon repair in hand, I was surprised to read this article by the venerable Roger Cicala over at Imaging Resource: http://www.imaging-resource.com/news/2013/11/14/inspecting-an-in-spec-lens-what-does-it-mean-and-could-factory-service-be

 

Perhaps I got lucky? Or they do a bang up job when it’s on my dime? Or maybe Nikon actually has some good test gear for lenses, but not bodies? Time will tell, since I still need to send my 17-55mm lens in!

D7100 practical bit-depth

More test results from this past week.  I already know that 14-bit isn’t any better than 12-bit at base ISO on the D700.  Well, let’s just make sure things haven’t changed with new gear.

There is (quite wisely) no “uncompressed” raw on the D7100.  But if you’re foolish enough to want to waste space, there are “losslessly compressed” and “compressed” modes, in addition to being able to select between 12 and 14 bit files.  My preference is the smallest file, since that helps the buffer dump to the card faster.  Lets see if I lose anything choosing 12-bit compressed (allegedly lossy) vs 14-bit lossless, first just comparing the overall scene before manipulation:

sidebyside

There’s a pretty good hot spot in between those trees.  Let’s dial down the exposure and see if one setting is capturing more in the highlights:

12 bit lossy14-bit lossless

Can you tell the difference?  There’s no posterization.  Now you can complain that the highlights didn’t blow, however, the point is that even in the 12-bit lossy version, there’s more highlight than I need.  Unless you’re doing something wrong, you probably don’t need 14-bit for highlights with the D7100.

Now let’s look at the shadows (artificially pulled up in post):

14-bit_lossless_shadow12-bit_lossy_shadow

Not seeing anything different here.

Now the point is not that there’s no difference.  The point is that for actual real world shooting, there is no appreciable difference.  Don’t waste your time or card space on 14-bit files.  If the review sites were smarter or more honest, they’d tell you the same.

Of course, if you want to come up with a reproducible test with real world repercussions, please, by all means do so.  And share your results like I have!

Here’s my original raw files if you want to play with them yourself.