 Sam Endicott |
Sears 60-300mm Lens Questions I have a Sears 60-300mm Macro Zoom lens. I am having trouble figuring out how it works. Sometimes when I am focused way out the circle in the middle is half dark and half light, and it varies from top to bottom. I have taken a roll of film with it, and it seemed all right - just some of my pictures came out blurry but I just figured it was because I didn't know what I was doing. If anyone can help, please do. Thanks for everything.
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Bob Cammarata |
It's common that when half of the focusing ring goes dark -when shooting macro or with extremes in telephoto - it means that light levels are low. While this may be an annoyance, it doesn't affect the outcome of the photo, other than making it difficult to lock in on your critical focus. What I've found helpful is to carry a small flashlight in my camera bag to add a little more light to my macro subjects to get the focus just right. This additional light eliminates the darkening of the focus ring and allows me to focus on the components most critical to the photograph. Then, I'll turn off the flashlight and take the shot.
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Kip T. Berger |
Back in the '70s and '80s, it was very common for SLRs to have split circle (split prism) viewfinders. Such viewfinder screens feature a circle, bisected by a usually horizontal line, in the centre of the screen. To focus the camera, you find a high-contrast vertical line (eg: edge of a wall, a tree trunk) and look at it through the viewfinder. You then adjust focus until the line appears unbroken in the split circle. Split circle viewfinders use a pair of tiny prisms set in precise positions in the viewfinder to achieve this effect. They’re arranged such that the image you see lines up (becomes coincident) when the line is correctly focused on the plane of the screen. Some cameras use four prisms so you can look for both horizontal and vertical lines and some use prisms mounted at 45 degree angles. Sometimes microprisms are used - even tinier prisms which give a textured look when the image is not in correct focus. All these types of manual focus assist aids make it much easier to focus manually, especially when light levels are low. The primary disadvantage of all prism-based focus assist aids is that they can stop working and black out (become so dark as to be useless) when used with certain slow lenses, long telephotos, teleconverters or extension tubes, because of the angles at which light is entering the camera from the lens. They may also require some exposure compensation because they may affect the amount of light reaching the camera’s internal light meter.
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Mark O'Brien |
If your photos came out blurry -- it may be because the camera was not mounted on a tripod. Shooting a 300mm lens handheld is almost a guarantee that you will get blurred images. Since these cheaper zooms don't have large maximum apertures (usually f 4.8), you end up using slower shutter speeds to compensate. If you are shootinga 300mm lens hand held, then your suggested slowest shutter speed would be 1/250 - 1/500 sec. On a tripod, it doesn't matter. So, my suggestion is to buy a decent tripod -- one that is sturdy and not too darn cheap. I highly recommend the Bogen series tripods.
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