Sony A6400 APS-C cameras and the reciprocal rule

[Lee H]

Hello everyone

I am struggling for sharper images in dull light and I know ISO plays a part in this. I seen an interesting video on YouTube were this guy mentions shooting in M auto ISO (reverting back to Manual ISO if need be) with shutter speed double the length of your lens when using an APS-C body. So for me using the 200-600 the minimum would be 1/250th of a second. Can anyone shed any thoughts on this method?

 

[Lee H]

For you, shutter speed when zoomed to 600 would be 1/1000, since 600mm X 1.5 for the APS-C sensor is 900mm. If you go to double it'd be 1/1200. It would be 1/300 or 1/400 at the short end. When shooting a zoom, it can be cumbersome to try and keep up every time you twist the ring. Just keep it at the fastest shutter for now until you get used to it.

His rule of double will work, but is excessive to me. Many of us use an old rule from the days before we had stabilization. "Never shoot a shutter speed lower than the focal length of your lens." Minolta was one of the first companies to include a very basic effort at stabilization by including programming in their Maxxum series so the camera would recognize the lens and stop the shutter speed from falling below the focal length, when in program mode.

It's always best to shoot in a mode that gives you the most control. I am in Manual 99% of the time, even my programmed modes are based on Manual. Modern day ISO can be thought of as the equivalent to film speed, or at least it's applied in the same manner. We used to buy film in ISO (or ASA) 100, 400, 800, etc., the higher numbers being lower light film. Increasing ISO allows you to increase the sensitivity of the sensor, which allows more light in when shooting in darker settings. Auto ISO does so automatically, within the parameters you set. The downside is that, like films where increasing the speed added grain, increasing ISO will add noise. By using certain techniques, the photographer can reduce noise in the image to a manageable level. By manageable I mean to keep noise in the shot low enough that it can be addressed in post processing.

One of these techniques is to try and overexpose the shot, which allows you to darken in in post processing. This is called ETTR, or "expose to the right", the "right" meaning the right side of your camera's meter, or the + side. This doesn't actually reduce noise, but it helps hide it by lowering the exposure in post.

I switch back and forth between choosing my ISO and Auto ISO, but I have Auto limited to ISO 6400 or 8000. You'd want to play around with it and try a few different settings with your setup to figure out what works best for you. It may take a little time so try to practice things that won't leave, like landscapes and buildings.

Thanks so much for your in depth reply, very appreciated. I am out of the house at the moment but I am going to totally go through your reply and try what you said. Means a lot for the help Mate