Nikon D750 Field Test Part II

Nikon D750 Field Test Part II

Performance deep-dive: AF, high ISO, HDR, exposure and more

By Jeremy Gray | Posted: 11/13/2014

Introduction

In Part I of my Nikon D750 Field Test, I discussed the camera's handling, usability, and performance in good lighting conditions. The greater challenge for a camera, however, occurs in difficult lighting conditions, and the D750 delivers excellent results in these situations.

Autofocus Performance

The D750 features a new Multi-Cam 3500 II autofocus sensor, which is an improved version of the autofocus sensor found in the D810. It has a 91k-pixel RGB sensor to offer excellent scene recognition. The D750 is able to detect and accurately autofocus with numerous subjects in various lighting conditions. For dynamic area AF, the D750 can focus with 9, 21, or 51 autofocus points and also 51 points in 3D tracking AF mode. In instances where the camera cannot accurately focus on your desired subject, you can set the autofocus to individual points or group-area AF (a small cluster of points). Changing autofocus mode is easily done by pressing the AF mode button on the front of the camera body and using the command dials. You can change focus modes when shooting as the information is displayed in the viewfinder. Likewise, focus points are illuminated in the viewfinder when shooting.

Given the autofocus combined with the D750's strong auto-exposure performance, I felt comfortable leaving a lot of control up to the camera. There are situations when I don't have the time to manually expose and focus an image, and the D750 delivers quite well in these situations.

Autofocus in Low Light

The Multi-Cam 3500 II autofocus sensor found in the D750 is an excellent autofocus sensor for low light photography. The D750's autofocus is the best I've experienced, especially in low light. Even in dark early morning conditions with a teleconverter attached to my telephoto lens, the camera was able to quickly and accurately autofocus. As I mentioned in Part I, the D750 could even autofocus on a dark foreground before sunrise when I was shooting on the coast, and helped me quickly capture images that would normally take trial and error and patience to accurately focus manually. This manual focus time adds up, and the D750's autofocus capabilities allowed me to capture more images and spend more of my time concentrating on lighting and composition.

High ISO Performance

The D750's sensor performs very well in low light. The noise performance is great, but what I have found most impressive about the noise performance on the D750 is its consistency. There is minimal banding and false color at high ISOs. Also, the sensor provides high contrast and deep blacks even at high ISOs. The noise has a quality to it that looks fine in prints but is also easy to correct in post-processing. For my night photography, I rarely need to go past ISO 4000, and I can confidently say that the D750 provides good quality files all the way up to and beyond ISO 4000. Good high ISO performance with the D750 also makes shooting with auto-ISO an attractive option when working in varying lighting conditions.

The in-camera noise reduction is satisfactory, but it can sometimes eliminate an image's fine details along with the noise. With in-camera noise reduction off, there is a lot of detail contained within the image files. On the other hand, I recommend shooting with long exposure noise reduction enabled. The D750, like any camera sensor, is prone to exhibiting hot pixels during long exposures and long exposure noise reduction does a good job handling the issue.

Shooting in Auto: Auto Exposure & Auto WB

A camera's metering and autofocus system are critical to a camera's ability to be used successfully in full-auto mode. The D750's autofocus system is outstanding, and its metering is very good. With the D750, you can operate the camera in auto mode with or without the flash being used. In my time with the D750, I tried it in auto mode in different conditions and found the camera to perform well overall. However, there were a few instances where the camera's auto WB system creates images that were too cool in color temperature, particularly in low light.

Introduced on the D810, and carried over into the D750, is a new highlight-weighted metering option, which biases the exposure to help protect highlights and retain detail in those areas. I experimented with the highlight-weighted metering some, but found using exposure compensation will give similar, but slightly more consistent results. However, I feel that highlight-weighted metering would work well in very high contrast situations where the subject is itself within the highlight area. I liked using Active D-Lighting in high contrast situations too, as I discuss further down.

In my own shooting, I always purposefully underexpose as to ensure that I'm not losing any highlight details to clipping. I often shoot in rapidly changing conditions, so I try particularly hard to avoid missing the shot. When out in the field with the D750, I was often using my standard approach of excessive cautiousness that regularly leads to underexposed files out of the camera, which is why a number of my unedited gallery photos appear underexposed. On shots without using exposure compensation or otherwise purposefully underexposing, the D750 captured well-exposed images with excellent dynamic range.

Speed

Capable of shooting up to 6.5 fps, the D750 is a fast full-frame camera, being bested in fps shooting only by the flagship D4 series in Nikon's current lineup. For most purposes 6.5 fps is sufficient. In our IR testing, we found this burst speed to be accurate, at around 6.6 - 6.7 fps for Best Quality JPEG to even 14-bit RAW+JPEG. However, this speed is only useful if the camera can quickly and accurately autofocus, and as discussed above, the D750 is excellent in that regard. Shooting in AF-C mode, the D750 maintained autofocus well throughout a burst, and regaining focus quickly if focus was lost. The group-area AF mode, using a cluster of five AF points, works well for slow-moving subjects. I also found the D750's 3D tracking autofocus area to perform well when a subject was moving too fast to use a single point or group-area autofocus. I would prefer the autofocus area to be a bit wider though, especially when tracking fast subjects that may move in and out of the focus area during tracking.

The D750 has a somewhat small buffer of 14 images when shooting in the highest quality 14-bit lossless compressed RAW files, which echoes what we found in our lab results. However, when the buffer is full, the D750 can still shoot at a respectable 4 fps. In my own experience, this buffer is big enough. However, if I knew in advance that I would need a larger buffer, decreasing RAW quality to lossless-compressed 12-bit would nearly double the buffer to 25 images (22 in IR's testing) and compressed 12-bit would increase the buffer further to 33 images. Considering the size of RAW files, the buffer is both acceptable and impressive. The EXPEED 4 image-processing engine keeps things moving quickly when shooting.

Shooting with the SB-500 Flash

I was also able to try out Nikon's new SB-500 flash. The SB-500 is small but packs a nice punch and is fully compatible with Nikon's Creative Lighting System. I tested the SB-500 on the camera and was pleased with its ability to provide fill light on a sunny day. The small size means there's no room on the flash for a display, but there are still your standard mode options available via a switch. The SB-500 looks great and has a wide range of motion, more than enough for any bouncing application. On a standard pair of AAs, the SB-500 is rated to fire 100 times on average, which should be okay for most outings. The flash unit does not recycle very quickly, though. The SB-500 is rated to recycle between 3.5-4.0 seconds, depending on the type of battery used. With that said, the SB-500 is a great alternative to the on-camera flash without adding a lot of weight to the camera.

Active D-Lighting and In-Camera HDR

When faced with difficult and high-contrast lighting situations, Active D-Lighting works really well on the D750, and the camera is able to salvage a lot of detail in the shadows while still controlling the highlights. To achieve a similar end, there is a new 'Flat' Picture Control option -- easily accessed in the My Menu by default -- that tries to maintain shadow detail in high contrast lighting situations. The 'Flat' setting does achieve the desired effect, but it tends to remove too much contrast from the scene for my taste, and I quickly returned to using Active D-lighting instead. Also new is the 'Clarity' adjustment in the Picture Control options, which increases detail in the mid-range tones. With Active D-lighting and improved Picture Control options, it is easy to capture detail from shadows to highlights with the D750, and I felt confident shooting in high contrast situations.

The D750 also offers an in-camera HDR mode, although disappointingly only available if RAW file recording is disabled. The HDR works well, and the 'Auto' HDR option creates final images with a subtle HDR effect. I also tried the highest HDR strength option, and it does what it is supposed to, although with too much glow around fine edges for my own preferences. In general, given the D750's ability to bracket 9 frames at EVs of less than 2, creating your own HDR images would be preferred to utilizing the in-camera HDR option.

Shooting with Other Lenses

While the 24-120mm f/4 kit lens performs well for a lens of its type, I captured a lot of images with my own lenses. All of the lenses I tested performed well with the D750. I didn't need to fine-tune the focus of any of my lenses, but the D750 does offer focus fine-tuning options. A standout lens was my Nikon 14-24mm f/2.8G. The D750 has built-in distortion and vignette correction that helps wide-angle lenses deliver their best image quality. I also tested my 400mm f/2.8 lens with an attached TC-14EIII teleconverter. As stated earlier, the autofocus with this combination was quick and accurate, even in low light.

Video Performance

The D750 includes many of the D810's video features, including the useful Power Aperture control function that provides smooth exposure transitions when adjusting aperture and also auto ISO when shooting video in manual exposure mode. The D750 can shoot up to 60 fps at 1080p resolution. For time-lapse photography, the D750, like the D810, allows you to capture up to 9,999 frames with time-lapse exposure smoothing for blended, smooth transitions between images should the exposure shift during capture. While I'm not a videographer by any stretch, the D750 made it easy for me to shoot high-quality video, even in low light situations.

Stay tuned for an in-depth look at the D750's video recording features and performance soon!

Conclusion of Part II

While most cameras perform well in good lighting conditions, finding a camera that performs well in poor and low light is more challenging. The D750 strikes an excellent balance between high megapixels and great high ISO performance, and coupled with the good image sensor is an even more impressive autofocus sensor. The D750 outperforms the D4s in low-light autofocus performance on paper, focusing down to -3 EV compared to the D4s' -2 EV. While the D750 is not the overall fastest FX camera in Nikon's lineup, it remains a very agile camera out in the field.

What I like most:

• Accessible video features
• Great high ISO performance
• Excellent autofocus capabilities
• Active D-Lighting works well

What I like least:

• Autofocus area feels narrow at times
• In-camera HDR doesn't seem worthwhile
• Small buffer when shooting in lossless 14-bit RAW

Final Thoughts

Fitting an FX sensor into a relatively compact camera body means that there will be some compromises that have to be made, but the D750 delivers high quality, particularly in critical performance areas. The image sensor and processing deliver high quality image files at both low and high ISOs. The autofocus sensor is very fast and accurate over a wide range of lighting conditions. On the handling side of the equation, the D750 features a deep grip and a very useful tilting screen. For many different types of shooting, the D750 offers versatility and excellent performance. The D750 not only performs and handles well, but it also provides a great value. Overall, I highly recommend the D750 for anyone looking for a compact full-frame camera that does not skimp in critical performance areas.

[Note: Most images above have been post-processed to some degree. Click on any image to take you to a carrier page from which you can access EXIF data as well as the full resolution image as delivered straight from the camera. To see even more images -- all un-edited -- please visit our Nikon D750 gallery images page!]