BASIC focusing question

[Marc985]

I used my mom's camera with a quantaray 75-300mm lense today on manual focus for the first time. I was shooting some aircraft taking off. How come when I go all the way out to 300mm to get things in focus(and they're at a distance) you must turn the focus ALL the way to the right....is this focused? or am i doing something wrong?

Thanks,
Marc

(its an old camera a Nikon N4004)

[Clemmie]

As you say, this is At A Distance. It is quite likely, therefore, that the 'in focus' point is all the way at the high end of the focusing range (or 'all the way to the right' on most lenses). On most lenses, anything beyond about 30 feet away, will be in-focus at the 'infinity' stop on the high end. There are exceptions to that - like I have a Macro lens where anything beyond 10 feet is infinity, and a 500mm where beyond 150 feet is infinity.

The real question is: Was the image In-Focus in the viewfinder? If not, then you didn't focus.

It occurs to me, that you may be confusing the Zoom control with the Focus - as it sounds like the lens was 'in focus' at one point of the zoom range, and out of focus otherwise. Zoom and Focus are two separate things.

You know, of course, how to Zoom - right? The big barrel grip which rotates to change the composition, or zoom ratio - and it does this whether you're autofocusing or manual focusing.

The Focus is a separate control. On a lens that's made for manual focus, it will be a separate twist ring along the barrel - usually having a focusing distance scale.

On a lens primarily made for autofocus - as you seem to have here - you will do manual focusing by rotating the outer tip section of the barrel. You will note that this rotates independently of the rest of the lens body. Some rotate quite freely, while some are rather firm - and the total range of rotation is usually no more than about half a turn, stop to stop.

Go try that, and you'll soon understand Focus vs. Zoom. You have to adjust both, when shooting in manual focus mode. Basically, if the viewfinder image is in focus, then it's focused - and if it ain't in focus, it ain't focused.

[Marc985]

Yes i was dooing it right. Mom's Pulls to focus and the end rotates. It appeared to be in focus in the view finder. I think you answered my question at the top. It just seemed odd that everything far away would be in focus all the way to the end with no way to adjust it.


Thanks,
Marc