Ask Matthew
Our resident Nikon expert Matthew Richards answers your questions and solves your problems. If you have a Nikon-related question, email it to mail@nphotomag.com
Our Nikon savant Matthew answers all your questions
QI’m thinking of upgrading from a D750 to a D850, but am concerned about image noise being worse at high ISO settings. Does the deterioration start at around ISO12,800, or is it below? Stephen Mottram
ACompared with the D750, the D850 bumps up the megapixel count from 24.3Mp to 45.7Mp. That’s a big leap, requiring the photosites on the image sensor to be much smaller. They’re therefore able to gather less light and, when you push the ISO setting in low-lighting conditions, image noise is more noticeable.
Degradation starts pretty early on and, in my tests, the amounts of image noise look quite similar when shooting on the D750 at ISO6400, and the D850 at just ISO1600. Suffice it to say that the D850 is fabulous for capturing fine detail and texture, but it’s
not ideal for low-lighting scenarios when you need to keep your shutter speeds quick with high ISO settings. Intriguingly, despite having the same high megapixel count as the D850, the Z 7 creates cleaner, lowernoise images at high ISOS.
QI’m after a Gitzo Systematic Series 3 tripod for use with my D750 and 500mm PF lens. It has a 25kg load rating, so why does Gitzo suggest a max focal length of 400mm? Yazdi Pajnigar
AI’d have no qualms about using a Gitzo Systemic 3 tripod with the AF-S 500mm f/5.6e PF ED VR. At 1460g, it’s less than half the weight of Nikon’s AF-S 500mm f/4e FL ED VR
– the Gitzo should also support this. Gitzo’s series numbers relate to torsional flex. The thicker legs of series 4 and 5
tripods help to further reduce any twisting movement to even more negligible levels. This can help to ensure accurate positioning when using very long telephoto or highmagnification lenses. Even so, Gitzo has assured me that the series 3 tripods are entirely appropriate for use with your camera and 500mm lens, along with the bonus that they’re a bit lighter to carry than series 4 and 5 tripods.
QIt’s simple enough to crop images to any aspect ratio in Photoshop, but is it possible to shoot at different aspect ratios with a Nikon D7200?
Ron Macalpine
AAs with other DSLRS, you’re limited to a 3:2 aspect ratio in regular, viewfinder-based shooting modes. The only alternative is to shoot 16:9 images. However, this requires selecting the ‘Take photos’ option in the Custom setting G4 (Assign shutter button), and then switching to movie capture Live View mode. It’s certainly not ideal, as you can’t preview
exposure settings for photos when in Live View movie mode, and autofocus is likely to be quite sluggish.
A better solution for changing aspect ratio in-camera, rather than on a computer, is to shoot in regular stills capture modes, then use the Trim function in the Retouch menu. This enables you to crop images with a choice of five different aspect ratios.
QHow do I set up the Focus Shift in my Z 6? There are no units of measurements associated with the ‘step width’ values, and I’ve read contradictory advice about using auto or manual focus.
Gary Irons
AAs also featured in the Z 7 and D850 cameras, Focus Shift is a great way of extending your depth of field.
It’s particularly useful in extreme close-up or ‘macro’ photography, where depth of field can be as little as 4mm or so. This can make it impossible to retain front-to-back sharpness when shooting threedimensional objects. A physical unit of measurement can’t be applied to the ‘step width’ setting, because it would vary at different focal lengths and starting focus distances. But the rule of thumb is that you’ll need to set a smaller step width and a larger number of sequential shots when shooting at shorter distances.
For close-ups, I’d recommend manually focusing on the closest part of the scene or object that you want to be sharp in the resulting image, and using that as the starting point for your Focus Shift sequence.