Tried fitting manual tamron lens with adaptall2 convertor to my d3000 but i get a lens not attached message.can this be overridden?

That depends on the lens mount. Tamron makes lenses for a variety of cameras. If it has a Nikon mount, it fits onto the N2020 just like a Nikon lens. If it has, say, a Canon mount, then it won't fit at all.

Promaster makes many different lenses. Some of their older lenses do not have the electronics to communicate with newer digital cameras, and you have to shoot in Manual mode. Could you tell us which lens you're asking about?

Tamron makes lenses with a variety of mounts. A lens with a Canon mount, for example, will not fit onto a Nikon camera. Assuming you have the lens with a Nikon mount, it will work fine on the D3000. Be aware that the D000's smaller sensor will make the lens appear as a 42-300mm lens would on a 35mm film camera.

Assuming the lens has a Nikon mount, it will fit on the D3000. Tamron makes their lenses with a variety of mounts, so that one with a Canon mount, for example, won't fit onto a Nikon body.

This lens lacks an autofocus motor so you'll have to focus manually. Other than that, it will work fine. It's not the sharpest lens available, but it's also not the most expensive.

Assuming the lens has a Nikon mount, yes.

The Nikon D3000 does not have a focusing motor built-in, relying on the lens to have a motor. The Tamron AF 55-200mm does not have the necessary motor; it only auto-focuses with Nikon cameras that have the motor in the camera body.

For Nikon lenses, you need lenses designated AF-S. For Tamron, you need lenses designated USD and/or BIM.

That probably wasn't the answer you wanted to see, but there it is.

ALL Nikon AFS branded lenses are compatible with the D3000. The AF lenses are usable in manual mode. Sigma, Tokina and Tamron lenses without the built-in motor are manual mode as well.
To be sure, check the manufacturer;s websites.
Hope this helps,
Andrew

Hi,
This lens and ANY Nikon lens that has AF-S (built-in lens motor) in it will work with the D3000. In addition, some of the newer Tamron, Sigma and Tokina lenses that have the motor built in will work.
Be careful though in holding the heavy lens simply by the DSLR grip. The lens mount may not be able to support the strain.
Hope this helps, Andrew

Only if you get the version with the built-in autofocus motor. The D3000 lacks a mechanical AF coupling so AF lenses which need to be driven by a motor in the camera body will require manual focussing.

Either way, you're far better manually focussing the Quantaray/Tamron 70-300mm: the AF performance is very slow, very noisy and hunts around a lot to achieve focus.

Although the Quantaray and Tamron versions are identical lenses, if you have to buy this low-quality budget model then go for the Tamron: it's absolutely no better lens quality (and usually the same price), but the manufacturer's warranty from Tamron is much better than Ritz and is internationally valid. If you resell the lens then the Tamron will have some value (not much though) and the Quantaray will be near worthless as it's not so widely known, and has a poor reputation amongst those familiar with the brand.

"Cheap" isn't always the same as "good value"...

if it is an auto focus lens that works on one eos camera, it should work on almost all of them. the only known exception is that some high end extenders will not fit the eos1dmarkII as it protrudes into the opening too far.
but a good rule is that if it fits without any obstruction issues, it should work. try cleaning contacts on the lens and camera body. if that doesn't fix it, talk to Tamron. you can use it manually, but will not be as easy and you would get less predictable results.

my suggestion is to always go with lens from camera maker.

sounds like there is an issue with the tamron lens. not the camera.
good luck
mark