Can you use nikon sb25 flash with d40 dslr?

You should be able to use your SB-22 with your D5000, however you can only use it in the manual mode since it is not a TTL speed light. That means you will need to manually set both the camera and the flash unit. I have done that successfully with an SB-25 on both my D800 and D90 in a pinch, but you should consider investing in either an SB-700 or SB-910. They are allot more versatile.

If you're worried about the trigger voltage, it's safe according to this list: http://www.botzilla.com/photo/strobeVolts.html

Basically, you put batteries into the flash, put it into the flash mount on the top of the camera, turn everything on, select a flash mode, and start shooting.
The flash comes with a detailed manual describing its operation. There is a section in the camera manual describing the various flash modes. The SB-700 is fully compatible with the Nikon iCLS system, which includes the D3100.

Since you asked a general question, I can only give you a general answer. If you have any specific questions, please feel free to ask them.

Walmart stores still sell that camera. see: http://www.walmart.com/ip/Nikon-D40-Slr-Camera-Kit/5607412
You can also purchase it at Amazon on line. at: http://www.amazon.com/s/?ie=UTF8&keywords=d40+camera&tag=googhydr-20&index=aps&hvadid=4645848837&ref=pd_sl_6lzr40qz09_e

Parts = http://www.bhphotovideo.com/c/search?Ntt=D40+Camera&N=0&InitialSearch=yes
Parts = http://www.porters.com/catalogsearch/result/?q=d40

You can also try Pawn Shops as cameras are gotten rid of all the time.

You interested of selling yours to me? I have one with cracked, and wishing to find a broken SB-400 to replace my part. Any offer if appreciated! Sincerely, Simon( utwicky at gmail dot com)

I realize these aren't the answers you wanted to see, but the D40 does not have any live view capability, nor does it shoot video. Nikon intended the D40 as an entry-level dSLR, with a minimal feature set. In fact, they didn't introduce the video until the D90, introduced more than two years after the D40. The least-expensive Nikon dSLR with both of these capabilities is the D5000.

It sounds like you're trying to use the SB-600 off camera, as a slave flash. While the SB-600 does indeed have slave capability, the D40 does not have the ability to function as a commander. Thus, the SB-600 is being triggered by the D40's pre-flash.

As stated above, the D40 does not function in commander mode. You can mount an SB-800 or SB-900 flash unit, which will function as a commander as well as a flash. Or you can mount an SU-800 commander unit.

Alternatively, you can switch the D40 to manual flash mode so as to eliminiate the preflash. However, you will then have to calculate the proper exposure yourself.

The Sb-80dx is not compatible with the d40x. You neen Sb600 or higher.

Yes. The SB-600 instructions don't mention the D60 because the SB-600 came out before the D60 existed. Bear in mind that the D60 does not have a commander mode so you can't use the SB-600 as a slave.

Basically, as far as the SB-600 instructions are concerned, just pretend that you have a D40.

no