Sony Nex 6 with 50mm upgrade.

Started Feb 8, 2013 | Discussions thread
EinsteinsGhost
EinsteinsGhost Forum Pro • Posts: 11,977
Re: Sony Nex 6 with 50mm upgrade.

Fredy Ross wrote:

Thanks all and now I understand and will use manual as I live in a shopping centre and have plenty of opps to practise. I had just upgraded the camera and the lens and went to buy petrol taking some photos from the car in different lighting. I just wanted to see how fast the camera focused. People walking in bad light were too blurred and this place was well lit up so I tried it. Just used it so you could see the exif information not for a photo contest. Personally I don't think the upgrade made any difference as before I went I took my granddaughter and it was erratic in fast or slow focusing. I guess manual ISO is the way to go although annoying. Never had this problem with my canon dslr cameras over the years except when using live view which is far too slow.

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fredyr

You could use Auto ISO. But as I pointed out, there are two issues to consider. First is relatively slow shutter speed to capture action (motion blur). Since the camera is deciding on the shutter speed, it is selecting the slowest recommended shutter speed for the focal length (for 50mm lens, it is 1/80s) before bumping up the ISO. In other words, also selecting the lowest needed ISO (in this case, ISO 250). This does not appear to be an issue in your example.

Now, what may be the issue is limited depth of field. At focusing distance of 30 ft (my estimate), 50mm lens and f/2, you're looking at a DoF under 10 ft. Now, if you were using the slower kit zoom (18-55 f/3.5-5.6) at 50mm f/5.6 (or even this 50mm/1.8 at f/5.6), the DoF will triple. But in an effort to maintain good exposure the camera will select higher ISO (1000). Now, this will provide you with an impression of things in focus (except if it were related to motion blur which can only be addressed via faster than 1/80s shutter speed).

My recommendations, keeping in mind that you prefer Auto ISO:

- If your concern is to freeze movement, use shutter priority. Keep it at 1/125s or faster.

- If your concern is to capture more in focus (larger depth of field), regardless of motion, use aperture priority. Choose smaller aperture to allow more in focus (also read up on hyper focal distance).

- If you want both, I would skip Auto ISO (go to manual ISO), keep aperture priority, select DoF as desired (by selecting the appropriate aperture) and adjust ISO to control desired shutter speed (1/125s or faster).

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