Sabtu, 29 Maret 2014

Nikon D4S - a hands on review

The first noticeable difference between the D4s from the D4 is the new sound of the motor clipping along at 11fps. The change in sound is probably attributable to the redesigned mirror box built to accommodate the faster speed by shortening the mirror travel distance. The other thing that came as a surprise was how long the D4s could keep on shooting and processing RAW files when there was a fast card in the slot. Nikon may have to do a take on the Energizer Bunny ad for the D4s.  These were the most immediately noticeable differences.

Here is a Nikon D4s sitting on my studio equipment cart ready to go to work. 
On the surface the D4 and D4s don't look so different, aside from a redesign of the smaller joystick controls on back, and minor tweaking to both hand grips. The differences are primarily inside.

Here are some of the improvements in the D4s:

- The 51-point autofocus system remains the same as the D4, however it adds a new Group Area AF mode grouping 5 points together to act as one unit to improve AF ability in confusing areas.

-  The D4s shoots at 11fps with continuous AE and AF.

- The mirror assembly has been redesigned to accommodate the increased speed to 11fps and has a side benefit of keeping the mirror in its open position for a longer time between shots thereby minimizes the blackout time caused by the mirror in the up position.

- There is a new Expeed 4 processing engine, and while the megapixels remain at 16.1, it has been redesigned to work even better in low light so that a new top extended ISO speed of 409,600 has been added. The full range is 100-25,000 with extended from 50-409,600.

- The D4s takes a new battery, the EN-EL18a, to extend use time out to 3020 shots, up from 2600 from the older EN-EL18 with which it remains compatible.

- There is a new uncompressed 12-bit RAW mode for capturing smaller RAW files that are 1/2 the size of standard uncompressed RAW files. Handy if you want to speed up workflow or save storage space. In addition there is the standard 14-bit compressed and uncompressed files, JPEG, and TIFF.

- An auto-ISO feature has been added and works when the camera is in manual mode. I find this handy when I want to lock in a specific shutter speed and aperture combo and let the ISO float a bit to keep the exposure consistent, as sometimes needed with time-lapse photography.

- Addition of a 1080/60p video recording for up to 10 minutes at 42Mbps or 20 mins at 24Mbps



We had to improvise some more extensive testing situations to see the improvements in low light shooting, and auto-focus.

I found that the upper limit of the D4s without much, if any, correction for noise is about 6400 depending upon the lighting situation, of course.

Download a high res version of this image by clicking here.

You might be able to get away with an ISO of 51200 after applying some noise reduction and improvement techniques in post processing.

This is an image shot at ISO 51200 with post processing corrections applied. Download a high res version of this file by clicking here.
Then there is the new top ISO of 409,600. It might make for attention getting copy in a press release, but I don't see much use for it given the results I've seen.

This is what an ISO 409600 image looks like from the D4s -- flat, ultra noisy, with color casts. The ultimate usage is going to have to be very small for the photo to be usable at all, even after applying some corrections. 
This is a full size crop from the image above it to show how the noise level from ISO 409600 appears. Have fun fixing that!
Putting the D4s to work:

The most obvious use of a camera like the D4s is fast-paced sporting events and wildlife photography. My own commercial work is different from that  consists mostly of lifestyle photography, over 90% of which I currently do with a D4, often shooting over 4000 frames per day. I prefer working with available light and like to keep the models constantly moving to add a feeling of spontaneity to the resulting images. The excellent low noise and low light capability, superb auto-focus system, and super fast 11fps motor make the D4s an absolutely perfect choice for this type of shooting. The situations are similar to what a wedding photographer might face in candid shooting, or an events photographer working in low light. With this in mind I decided to test the D4s over four different lifestyle shoots with varying available light. Some of the results are below.

This sequence shows what a camera is up against in a fast moving lifestyle situation that led up to the finished image below. The D4s was shooting at 11fps. There are 12 shots in the sequence so it took only a hair over 1 second. The scene is entirely back lit from a window and no fill from the front. The 85mm lens was set to an aperture of f/2. At this close distance that left zero tolerance for depth of field. A continuous focus point was placed on the model's eye and had to keep changing the distance as the model's head moved forward towards the camera and her hand came up to further block the view. Although the model's face only moved forward four or five inches, with the distance of the lens, the focal length, and speed of action that is considerable. There were actually 118 images in the entire sequence of the model laughing and rocking her head back and forth, and every shot remained in focus. 



Not only is this scene back lit, but I am shooting past some out-of-focus foreground glassware to create the softness surrounding the models. As always, I instructed the models to keep moving and had to follow with a continuous focus point placed on the woman's eye. 
It wasn't bad enough that this scene was lit only by the window behind the model, I decided to add in a tungsten lamp to create a flare and flatten the contrast on his face even more. The 85mm lens was set to f/1.8 and focus placed on the right eye with plenty of obstructions caused by the foreground computer screens. 

To obtain a shallow depth of field along with the blur motion in the person walking I put a variable ND filter on the 85mm lens set to f/1.8 and turned the filter until it gave me a shutter speed of 1/20th second to create the blur. The foreground model was instructed to hold her pose and not move. This scene was taken in a very dimly lit scene with light coming only from the windows behind the models.  

We set this scene up in the studio just to test the auto-focus performance of the D4s. The scene is entirely back lit with tungsten lamps, smoke was added to add a layer of haze, and the rest of the room was blacked out for darkness. The camera was set to ISO 1600 with the 85mm f/1.4 Nikkor lens. Blazing away at 11 fps, the D4s almost never missed its focus. 
Photographed with a 35mm lens at f/1.4

Typically in a scene like this I would have a difficult time achieving focus on the model's eye. The D4s consistently found the spot and kept the eye -- in this case the eyelashes -- in focus.  And in the scene above the model was not sitting still, but constantly moving about. 
Conclusion:

On paper the differences between a  D4 and D4s appear so tame you begin to wonder why Nikon would even bother introducing a model change. But the D4 series is the workhorse cornerstone of many pro photographers, me included. It probably isn't a question of whether of not the changes are needed. Rather, it is more a question of whether or not the changes improve your workflow. For me, moving from 10 fps to 11fps is overkill. I still find the 9fps of the D3 more than sufficient. But there are photographers shooting fast action sports and wildlife for whom this improvement would be significant. 

Working as I do in low light with high speed aperture lenses, my chief concern was with the improved AF of the D4s. This is one of the reasons I tested the D4s over several lifestyle shoots with dim back lighting. In these situations I know I am going to lose a large percentage of the take to missed-focus so I always overshoot the scenes as a way of bracketing the focus. The D4s was considerably better at delivering in-focus results in these situations, so much so that by the fourth lifestyle shoot I began feeling comfortable enough to cut back on my normal focus bracketing.

I also appreciated the faster write speed to high speed memory cards. This allowed me to keep on shooting while as long as the models continued to deliver the action. Having to ask the model to stop and wait while the buffer is transferring to the memory card is can be disruptive to the fluidity and mood of a scene. 

Bottom line question is: Based on the improvements, would I trade in my D4 for a D4s?  If there were enough life left in my D4, I would say probably not. The new conveniences of the D4s, while nice, are not something I absolutely need. If my D4 were older, then I would do the trade even though the newer D4s model is priced around $500 higher at $6496.95. The extra cost would most likely be made up down the road when the Nikon D5 comes out. 

The lineage of Nikon flagship models, the D3, D3s, D4, and now the D4s, are absolute workhorses, and best of breed at what they do. In the hands of a working pro, this camera represents dependability and exceptional image quality under the worst circumstances you can throw at it, qualities that have endeared themselves to Nikon users since the original Nikon F.

85mm lens at f/1.8
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