I am going to ask 2 questions although the first i think i already know the answer...just want it clarifying

1. the aperture rating on a lense...does that denote the lowest value at both extremes i.e 70-300 tamron f4.5/5.6. Is that 4.5 at 70mm and 5.6 at 300mm??

2. I am struggling with a concept. If i was to set me camera at say f11 so that most of the picture was in focus but wanted a very long shutter speed for a `flowing` effect, maybe 2secs. How can i get the picture so it isnt too bright without altering the ISO setting to extremes where there is excess noise in the picture. I have read that working in manual `exposure compensation` doesnt work so thats not the answer.

These might be easy questions so sorry to sound dumb

Regards

Roy

Hi Roy,

You are correct on Q1, the f-stop numbers are the lowest at each end of the focal range.

For Q2, the best way to get a long exposure at a large depth of field is to use one (or more) Neutral Density filters. They allow you to cut the amount of light hitting the sensor/film and therefore requiring a longer exposure. Perfect for flowing water or any other movement.

Rich

Thats great thanks. I bought a filter when i got one of my lenses but never really understood what it was for. May have to have a look at it and do some experimenting,

You will want your ISO set to the lowest number for your camera (usually 50/100/200) to give you the best possible quality. Raising it only reduces the exposure anyway, which is the opposite to what want.

Yes i have misinterpreted the ISO setting. The lower it is the less light gets in. Mine is 200 on mine as its a fairly low end SLR.

I am beginning to realise that there is alot more to learn although i am getting there...slowly