Manual exposure mode, the one where you are in complete control of your photos. Sometimes you need a little helping hand, and same exposure new aperture is that aid.
You know “full” manual where you determine the shutter speed, aperture and ISO. So this helpful same exposure for new aperture function makes your life just one bit simpler. It automatically achieves consistent exposures, even when you are completely focussed on your subject.
Same exposure for new aperture
Let’s say you shoot portraits, and have a few different favourite lenses such as a 50mm, 85mm, 100mm or 135mm. Depending on which specific lens you have the maximum aperture is more than likely different for each lens.
So you start the shoot with an EF 85mm f/1.2L II USM, then switch to the EF 135mm f/2L USM. If you were shooting wide open at f/1.2 with the 85mm the change to the 135mm, means you’re now at f/2. As a result you need to remember this and change the ISO or shutter speed to accommodate the loss of 1.3 stops of light.
Wildlife (and sports)
Now let’s look at a wildlife example. You have the EF 100-400mm f/4.5-5.6L IS II USM on your EOS 7D Mark II, and EF Extender 1.4x III in your pocket for a bit more reach. The photo above is exactly that, EF 100-400mm f/4.5-5.6L IS II USM with an EF Extender 1.4x II giving f/8 maximum aperture.
You shoot manual, and start at 1/2000s f/4.5 ISO 400. Then you zoom in a little and the lens aperture drops from f/4.5 to f/5.6. That’s 2/3-stop less light and a slight underexposure. Your subject then moves further away and it’s time to put the extender in, so now your are at 640mm and that means f/8, some 1.6-stops less light than you started at.
The helping hand
If you’re shooting fully manual you might be skilled and conscious enough to recognise all these changes, and compensate ISO or shutter speed without a thought. But what if you don’t?
Same exposure for new aperture is the most amazing helping hand you haven’t heard of. You’ll find it in the custom functions of the EOS 7D Mark II, EOS 5Ds/5Ds R, EOS 5D Mark IV, EOS-1D X Mark II and EOS R. What it does is help you out, by avoiding underexposed results in both the portrait and wildlife examples above. I use it to vary my ISO just a bit.
Same exposure for new aperture, recognises that the aperture changes as you zoom, change lenses or add an extender. Take the 100-400mm f/4.5-5.6L IS II USM, you loose 2/3-stop of light as you zoom from 100 to 400mm. How awesome would it be if the camera just raised the ISO from 400 to 640 to maintain the same exposure. Yes that is exactly what it does.
Now for the portrait photographer, swapping lenses from f/1.2 to f/2 and the ISO goes from ISO 100 to ISO 250. And you only needed to concentrate on your subject as the exposure will be the same automatically.
If you prefer, you can have the camera adjust the shutter speed, or ISO. Some cameras have the option for adjust a combination of ISO and shutter speed. My choice is ISO only.
Who is it for?
Photographers who shoot in manual exposure with fixed ISO, who have lenses with different maximum apertures or a zoom that changes aperture as they zoom.
- For the variable aperture zoom lens – this is brilliant.
- For the prime lens shooter, who turns the camera off to change lenses, this is not going to help at all. But if you keep the camera powered on when changing lenses or adding an extender it’s a lifesaver.
I use this and on a recent portrait shoot I changed from an 85mm f/1.8 to my EF 24-70mm f/4, and the camera simply boosted the ISO from 100 to 500.
Limitations – the maximum ISO is the highest value you have permitted for the ISO auto range, similarly the minimum ISO is the minimum you have allowed for auto ISO.