A Site for Photographers by Photographers

Community > Forums > photo.net > Lenses > Promaster 100-400 4.5-6.7 w/...

Featured Equipment Deals

Basic Printing with Lightroom (Video Tutorial) Read More

Basic Printing with Lightroom (Video Tutorial)

Learn to print your images directly from within Lightroom. This video tutorial covers the basic settings (page borders, watermarking, print resolution, and paper and printer preferences) for creating...

Latest Equipment Articles

4 Outdoor & Adventure Photo Packs Read More

4 Outdoor & Adventure Photo Packs

Photo packs have come a long way in the past decade, especially those that are targeted toward outdoor and adventure photographers. Alaska-based adventure photographer Dan Bailey takes a closer look...

Latest Learning Articles

5 Tips for Combating Red-Eye Read More

5 Tips for Combating Red-Eye

Red-eye doesn't have to ruin your photos. Learn 5 simple tricks to avoid and eliminate this undesirable photographic effect.


Promaster 100-400 4.5-6.7 w/ Elan IIe

Tim Robison , Aug 20, 1999; 08:56 p.m.

I recently purchased a used Promaster 100-400 4.5-6.7 lens used at a great price. When on the Elan IIe, at 400 the aperture reading is 5.6. My question is, is the lens actually at 6.7 when I get the 5.6 reading, or should I manually select the 6.7 aperture? This lens is the same as the Vivitar 100-400 and the Phoenix, anybody with experience with this lens would be appreciated if they would share their knowledge...

T. Robison

Responses

Jim Strutz , Aug 20, 1999; 10:57 p.m.

Tim,

This is fairly common with small aperture zooms. They report f:5.6 because most Canon EOS cameras (and others as well) are designed to NOT allow auto focus with smaller apertures. Canon builds them to reliably AF down to f:5.6 and doesn't want people to complain about erratic performance with slower lenses.

In actual practice most EOS bodies will AF as low as f:8, but only if there is sufficient light and contrast. I wouldn't worry about it. AF performance will not be the greatest but the exposure will still be accurate even with the wrong f:stop being reported.

Back to top

Notify me of Responses