Df burst rates varying by card

The contenders

I chose not to test as many cards as last time, when I tested the D7100.  Partly because I hope that anyone spending the money on a Nikon Df is using a good quality card to go with it, and partly because the initial results made it fairly clear that performance correlates between the cameras pretty well.  Also, the Df was generously on loan to me so I had to be selective about how I used my time with it.

Test setup

Same test setup & method as before, in the Nikon D7100 test.  The only difference is that picture area was set to FX, not DX.

At ISO 100 the average file size was right on 19.8 MiB.  That rose to 25.6 MiB at ISO 800, and then to 27.4 MiB at ISO 6,400.

The results

ISO 100

Points of interest

  • Look at that big sexy buffer!  My D7100 is having severe performance anxiety after seeing this.
  • More seriously, note how consistent the shots are when initially buffer-bound.  Much more consistent than the D7100.  There’s no reason for the D7100 to drop frames and stutter when there’s buffer space available – and the Nikon Df proves it.
  • The SanDisk Extreme Pro 95 MB/s 32 GiB takes the crown for average speed, by a noticeable margin – it gets 31 shots at full speed and then ~2.3 FPS after filling the buffer, vs the ~29 to ~1.9 FPS of its younger sibling the SanDisk Extreme Plus 80 MB/s 32 GiB and the Lexar Professional 600x 128 GiB.
  • Props to the SanDisk Extreme 45 MB/s 16 GiB for consistently pulling ~27 + ~1.7 FPS.  When you consider its reliability in contrast to the Lexar’s unreliability, and the fairly small margin between the two in performance, it’s surprisingly competitive.
  • Note the inconsistency of the Lexar Professional 600x 128 GiB.  I double-checked my data on this to be absolutely certain, and it’s no mistake – it really does have these very noticeable glitches.  (I also noticed these, audibly, when recording the shots – it’s quite obvious when it suddenly stops taking photos for a good second or so)

ISO 800

Points of interest

ISO 6,400

Points of interest

Compared to the D7100

Here I’ve re-scaled the Nikon Df‘s results to the first 10 seconds of shooting, to match the D7100’s.  It also gives a better impression of just how much bigger the Df’s buffer is.

Points of interest

  • There’s a much bigger difference on the Nikon D7100 between the SanDisk Extreme 45 MB/s 16 GiB and the other three cards, than on the Nikon Df.  This suggests that either the Df is better at utilising slower cards, or – and I think this is in fact the case – simply less demanding and less able to utilise faster cards.

    With the SanDisk Extreme Pro 95 MB/s 32 GiB the Df’s write rate is right about 46 MB/s, whereas the D7100’s is ~56 MB/s.  It appears that the Df is limited to ~46 MB/s.  I posit that the Df supports only UHS-I SDR50 or DDR50 – either way providing a theoretical bandwidth of 50 MB/s – whereas the D7100 supports UHS-I SDR104 – providing a theoretical bandwidth of 104 MB/s.

    I believe the reason the Nikon D7100 doesn’t achieve 104 MB/s is because it’s actually limited by the card – a faster SD card should yield ~3 FPS, in theory (vs the ~1.9 FPS it achieves with the SanDisk Extreme Pro 95 MB/s 32 GiB).  I guess now I’ll have to find such a beast…  in theory something like the Transcend R95 MB/s W85 MB/s 64 GiB fits the profile.  I might have to acquire one for testing…
  • The D7100 is “losing” in FPS only because its files are bigger.  If you shoot in 1.3x crop mode you get ~15.4 MP, comparable to the Nikon Df‘s 16 MP, and thus presumably similar file sizes.  I expect you’d then get noticeably higher frame rates from the D7100 than the Df.  I may now go test the D7100 doing exactly that…


Unlike the Nikon D7100, this is viably a four-horse race.  Because the Nikon Df seems limited by a slower SD card interface, you don’t see nearly as much benefit from the fastest cards.  This makes it an interesting value proposition – the Extreme Pro 95 MB/s’s typically retail for about twice the price (per GiB) of the Extreme 45 MB/s’s, yet on the Df give you only one extra shot every two seconds (or four extra shots “in the buffer” before slowing down).  i.e. a ~20% performance increase for a ~100% price increase.

Likewise the Lexar Professional 600x 128 GiB seems slightly hampered.  It can’t quite get ahead of the SanDisk Extreme Plus 80 MB/s 32 GiB like it does on the D7100, so it loses that counter-balance to its unreliability.  It does still have a non-trivial price difference in its favour, however.

Consequently, my ranking of the four cards is slightly different to that for the D7100.  The SanDisk Extreme Pro 95 MB/s 32 GiB unsurprisingly takes first place, again, but this time its little brother the SanDisk Extreme Plus 80 MB/s 32 GiB comes in a respectable second – the Lexar Professional 600x 128 GiB concedes the position and falls back to third place.  Leaving, as before, the SanDisk Extreme 45 MB/s 16 GiB in fourth place.  But feeling like a bit more of a viable contender than it did in the D7100.

It does beg the question, however:  how slow can you go?  Would the SanDisk Ultra now actually be attractive?  I regret not testing it in the Df, in hindsight, because it’d probably put in a relatively good showing.  But I’m confident in saying it’s still a noticeably slower card, and I see no reason why its horrible lack of reliability would be in any way improved in the Df, so I continue to recommend against the SanDisk Ultras, and any like “no-name-brand” or so-called “budget” SD cards.

My final rank, based primarily on performance and reliability:

See also

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