I have my Nikon D7500 set to Manual Mode. I can change the shutter speed and it maintains the setting. When I change the aperture, the setting is not maintained and varies depending on the zoom of the lens. How do I stop the aperture from changing when in Manual Mode?
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1\$\begingroup\$ And the lens in question is? \$\endgroup\$– Romeo NinovJan 5, 2020 at 19:09
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\$\begingroup\$ Related: This answer to Why doesn't the picture become darker the more you zoom in? (Hint: with variable aperture zoom lenses, it does get darker.) \$\endgroup\$– Michael CJan 5, 2020 at 20:31
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\$\begingroup\$ Also related: I can't get the aperture to stay at f/4 and shutter speed at 1/1000 in manual mode on a sony a6000 and How do zoom lenses restrict their widest aperture at the telephoto end? \$\endgroup\$– Michael CJan 5, 2020 at 20:40
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\$\begingroup\$ "How do I stop the aperture from changing when in Manual Mode?" Set the aperture to the smaller of the max aperture values. Since you're using a 18-300/3.5-6.3, setting the aperture to F6.3 or narrower (larger number) will let the camera maintain the aperture throughout the zoom range. \$\endgroup\$– xiotaJan 6, 2020 at 0:07
1 Answer
Many lower-cost (or even more expensive but high zoom-ratio) lenses do not have a constant maximum aperture. They are constructed so that they have as wide as possible aperture when zoomed out, but the design compromises in their construction mean they are limited to narrower apertures when zoomed in.
I expect that's what's happening here: you have an aperture set which your lens provides at a wider zoom but which is not physically available when zoomed in, so it's doing the best it can.
If this is the case, your lens will have a designation like 18-140mm f/3.5-5.6G
. The "G" is a Nikon thing (and irrelevant here), but the other numbers are typical for all makes of lens. The first is the range of focal lengths in millimeters, and the second, f/3.5 to f/5.6, is the maximum available focal length at each end of the range. In between, of course, the limits will be somewhere... in between.
For more on this, see Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?
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\$\begingroup\$ This would be definitively the case if your lens says something like e.g. 100-400mm f/4-5.6 on it - that indicates that f/4 is possible at the 100mm end, but only f/5.6 at the 400mm end. Where the change points along the zoom are highly is dependent on exactly what lens you have, though... \$\endgroup\$– twalbergJan 5, 2020 at 19:03
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\$\begingroup\$ @twalberg Good idea -- I'll add that to my answer. \$\endgroup\$– mattdmJan 5, 2020 at 19:05
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\$\begingroup\$ @lestat1978 That settles it — 3.5 to 5.6 \$\endgroup\$– mattdmJan 5, 2020 at 21:57
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