Will a battery grip on D850 help with Autofocus tracking because of the higher fps rate?

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Dtsobel

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I have a D850. I'm thinking about buying the Md-d18 with el18 battery to up the frame rate to 9ps vs 7ps. I've heard contrary things about if this helps with tracking since there would be less blackout time when shutter is released
 
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The only time I've run my D850 without the grip was when it was new and the grip hadn't been released. I don't recall any difference in af operation once I added the grip. It's a difficult comparison to make given all the variables involved. To do it correctly, you'd have have controlled conditions that would repeat so that you could shoot the same thing with and without the grip. BIF aren't one of those things, just a minor change in the bird's flight path, angle on the camera, distance form the camera etc may have a change on the af performance which might lead to false conclusions. Then you have to consider the photographer's ability to stay on the subject. One test does come to mind that minimizes (but doesn't eliminate) the variables would be a race car doing laps. If you were to set up at a given location and shoot the same car as it makes lap after lap you might get an indication but it would be totally subjective. If there is a difference, I doubt it could be measured. Add to that any bias the observer may have, if you think there will be a reduction in AF performance, you will probably observe one whether it's really there or not.
 
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On another thread, someone mentioned snappier AF due to the battery power of the EN-EL 18. I have had a gripped D850 for quite awhile and am very happy.
 
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Dtsobel said:
I have a D850. I'm thinking about buying the Md-d18 with el18 battery to up the frame rate to 9ps vs 7ps. I've heard contrary things about if this helps with tracking since there would be less blackout time when shutter is released
Click to expand...
Well, the frame rate does increase with the grip and the larger battery. IMO, the biggest benefit when focus stacking would be less end to end time to capture the entire sequence of images which could help on breezy days or for skittish live subjects. IOW, if you capture say a 70 frame sequence in less than 8 seconds instead of 10 seconds there might in some circumstances be an advantage in terms of less subject movement.

Overall I doubt you'd make a big change to success of focus stacked images with the higher frame rate but there's no real downside and the higher frame rate can be very nice for action work.
 
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From what I can tell, there's little to no difference in AF performance with and without the grip. However, as Warren mentions, it's really tough to test. Also, I tend to think that if there were an improvement, Nikon would brag about it to sell more grips.
 
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Steve said:
From what I can tell, there's little to no difference in AF performance with and without the grip. However, as Warren mentions, it's really tough to test. Also, I tend to think that if there were an improvement, Nikon would brag about it to sell more grips.
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While we all might think that, truth seems to be that folks in Nikon's marketing Dept are permanently napping.....
 
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Oooops, I thought this thread was about the grip and larger battery helping 'focus stacking'..... as Gilda Radner's character on SNL used to say.... Never Mind :oops:

Guess I shouldn't post before coffee :)
 
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Dtsobel said:
I have a D850. I'm thinking about buying the Md-d18 with el18 battery to up the frame rate to 9ps vs 7ps. I've heard contrary things about if this helps with tracking since there would be less blackout time when shutter is released
Click to expand...

Purely theoretical :

If the black-out time is the same at 7fps as it is at 9fps, then shooting at 9fps means you have less mirror-down time so the AF should behave slightly worse.

If the black-out time is shorter with the grip, then, depending on how shorter it is, you should get about the same mirror-down time or a bit less, so the AF would behave similarly at best. I see no reason why this would be the thing, as in my observations, a Nikon DSLR has the same black-out time no matter at how many fps you are shooting.

From a "in the field" point of view, I don't think it makes any real difference.
 
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Dtsobel said:
I have a D850. I'm thinking about buying the Md-d18 with el18 battery to up the frame rate to 9ps vs 7ps. I've heard contrary things about if this helps with tracking since there would be less blackout time when shutter is released
Click to expand...
Largely in unison with others here, My experience would suggest no difference in AF performance with the grip and I've had my grip on the D850 since day one, for three years now. Despite the obvious lift in FPS that the grip and EN EL18 gives the D850, what I rarely read of is how much more improved the shooting experience is for folks in portrait mode with the grip attached (indeed, any grip on any body). For me and FWIW its the ergonomic improvement the grip gives that is consistently the biggest benefit.
 
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What affects autofocus performance is the ability of the camera to drive the autofocus of the lens and the ability of the AF sensors to detect lines of contrast. The first is helped by the AF module in the camera and the second is helped by the maximum aperture of the lens. The 500mm f/5.6 provides half as much light to the AF sensors as the 600mm f/4 lens and that does have an impact in certain situations and with certain subects.

While the EN-EL18 battery in a D850 is going to provide more current and maintain a higher voltage level during a sequence of shots it is not necessarily the gating factor in the autofocusing of the lens. It may make the AF module 20% more effective but that could still mean it was 15% less effective than the D5 AF module with the same battery, which I suspect is the case.

The grip with the EN-EL18 battery does increase by more than 200% the number of shots I can take without needing to change batteries. I also find it easier at the end of the day to recharge on ENM-EL18 overnight than 3 of the EN-EL15 batteries as a matter of convenience.
 
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I have a D850 and shoot sport with it on long lenses: Nikon AF-S 300m f2.8 II (non-VR), 200-500mm, Nikon AF-S 200-400mm f4. I've shot both with and without the grip. Where the difference in favour of the grip is with these long lenses, the bigger EN-EL18 battery can drive them a bit harder. At least more consistently when an EN-EL15 is at 50% or lower. Just like an electric lawnmower starts to struggle in the last 40% of battery (also have one of those which uses 2 x 18v 4.0w batteries).

Wish there was an objective way to measure the difference in focuse performance, but we're talking about milliseconds here and slightly erratic behaviour.

Also when shooting a game, the EN-EL15 won't last a whole game with a big lens. Worrying about when to change batteries and some lag on focus does not improve sport shooting. Still, if you are not going to shoot big heavy lenses, the grip and the EN-EL18 probably won't improve focus. With the big lenses, a D850 balances better. Also if you're shooting a D5 with the other hand, it's easier to have identical grip and identical battery requirements. Not having to worry about batteries during a game helps focus a photographer on the shoot and not the technology.
 
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Dtsobel said:
I have a D850. I'm thinking about buying the Md-d18 with el18 battery to up the frame rate to 9ps vs 7ps. I've heard contrary things about if this helps with tracking since there would be less blackout time when shutter is released
Click to expand...
No. The focus-tracking depends on the focus module component, the higher battery capacity and frame rate is of little to no relevance, there are only so many focus points in D850.
 
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I have shot the D850 both gripped and not gripped. With the grip and the 18 series battery, the higher fps was definitely noticed and appreciated. But I could not tell a difference in the ”snappiness” of the lens or the AF effectiveness. My typical lenses were the 300PF, 500PF, and 200-500 zoom. Some folks swear there is an improvement, but if there is, it made very little difference in the field.
 
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