Camera Labs

Heard from an acquaintance that it is not possible to set any aperture/exposure combination of choice on DX AF lenses even when set to manual focus and mode dial to M.
example: aperture gets locked at minimum f5 when lense set at 55mm (82.5mm), but exposue can be changed ( for nikkor lense). Possible to get f3.5 if zoomed out to 18mm (27mm).
But in manual SLRs it is possibe to set f2.8 even when zooming at 300mm.

If any of you plz tell whether this holds good at all? If yes then how to overcome it?

P.S. I tried it myself and faced same problem. But me not a DSLR user, unsure about all settings there in

Thanks,

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Jagadish_C
http://s1229.photobucket.com/albums/ee472/Jagadish_c/
http://www.flickr.com/photos/46710427@N07/

If I read your question correctly, you are referring to the maximum aperture range for a given lens...in this case, a kit lens or 18-55. You can set the aperture to any level you want in manual mode, however, you cannot get to an aperture that is bigger than the maximum for that focal range. With zoom lenses, the maximum aperture is always listed as a range - for example, 18-55mm F3.5-5.6. So the widest aperture possible for that lens at 18mm would be F3.5...you can't go any wider. You can however choose a smaller aperture - from F3.5 all the way to F22. If you zoom the lens to 55mm, the maximum aperture is now even smaller - F5.6. So you can't go any bigger than F5.6, but you can still manually adjust to as small as F22.

That "F" range listed next to the lens description will tell you what the maximum aperture is at the widest and longest ends of a given lens. If you want the ability to manually set a lens at F2.8, then you need a lens that has that maximum aperture, such as the 18-250mm F2.8. This lens has a constant maximum aperture of F2.8, and can achieve that F2.8 aperture throughout the whole zoom range.

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Justin Miller
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 200-500mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony NEX5N / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / Pentax K adapter / Konica K/AR adapter / bunches o' Konica & Pentax lenses!

Galleries:
http://www.pbase.com/zackiedawg

Thanks a lot Justin. Got the answer.
That means if more light or shallower DOF required then faster lense is the option.
May sound very stupid, but is this limiting of f related to only AF lenses or all lenses put on DSLRs? Asking this because checked my tamron 75-300 on my vivitar, set f4 and zoomed to 300mm. It seemed to work.

lense marking says 1:4 - 5.6 but f markings are from 4 to 32.

Thanks once again.

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Jagadish_C
http://s1229.photobucket.com/albums/ee472/Jagadish_c/
http://www.flickr.com/photos/46710427@N07/

Sometimes it depends on how compatible the lens and camera body are - I've heard of some older lenses being put on camera bodies where the camera can be set to 'F4', for example, but the lens' minimum aperture of F5.6 will still be used - it's usually a case of an older lens not being chipped to 'talk' to the camera and limit the aperture appropriately. Some older lenses cannot even be shot in Aperture Priority mode, only manual, because of this limitation. When shooting in Manual mode with these lenses that don't communicate with the camera, you actually need to set the aperture on the lens using the aperture ring, and are supposed to leave the camera in its widest aperture setting. Some cameras are different from others in this regard, depending on how compatible they are with older lenses or other mounts using adapters.

When in doubt, stick to what the lens' listed maximum aperture is, regardless of what the camera thinks it is doing!

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Justin Miller
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 200-500mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony NEX5N / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / Pentax K adapter / Konica K/AR adapter / bunches o' Konica & Pentax lenses!

Galleries:
http://www.pbase.com/zackiedawg

Thank you very much Justin for the clarification and patience. It was immensely helpful for me.
Exactly as you mentioned, I did set the aperture with the app. ring on lense. Viv being a fully manual camera, no way any synchronisation is possible through chip/electronically though the lense is Tammy AF 75-300 LD.

Regards,

_________________
Jagadish_C
http://s1229.photobucket.com/albums/ee472/Jagadish_c/
http://www.flickr.com/photos/46710427@N07/

If I remember from my film days with my old Pentax ME-Super, when you get a zoom lens with a maximum aperture range, like your F4-5.6 lens, if you set the aperture ring to F4, then zoom out, the aperture ring can't/won't adjust, but you will be getting an aperture of F5.6 since that is the maximum. The F4 setting of the lens' aperture ring will have no bearing, and the aperture ring will be essentially doing nothing until you adjust it past F5.6 - from F5.6 to F32, you will be adjusting the aperture, but once you go more wide than F5.6, the ring is just turning nothing. Only when you zoom back in will the maximum aperture open back up to F4. Most of the time, when shooting a variable aperture zoom like that, if I needed maximum light, I'd adjust the aperture wide open and leave it there - so when shooting wide angle I'd get the biggest aperture, and when I zoomed, it would adjust to whatever the maximum was for that focal length.

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Justin Miller
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 200-500mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony NEX5N / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / Pentax K adapter / Konica K/AR adapter / bunches o' Konica & Pentax lenses!

Galleries:
http://www.pbase.com/zackiedawg

That's a good tip Justin on wide open lens for all focal lengths.

Cheers

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Nikon D7000, D40X, Nikkor 18- 200 VR II, f3.5-5.6, 70-300 AF non VR, Kit Lenses.