I uploaded to my gallery some bad pictures taken with my D40 and 18-55mm F/3.5-5.6, default settings, Auto mode, same time, location and bright afternoon light condition as the good ones taken with a D50.
Are the shots with both cameras taken with the same lens, or different lenses? I've got two initial thoughts, is negative exposure comphensation turned on, on the D40? If different lenses, possibly a stuck aperture on one lens.
Check ISO settings on each camera, Opanda reports ISO 200 on the D40, but shows no ISO speed listed for the D50. Having the ISO on the D50 turned up a couple of stops would make the underexposure difference between the two cameras, particularly with some bias towards underexposure to begin with.
With the lens off the camera, look through it, and see if the aperture is wide open. Manually, and gently, move the little lever (this controls the aperture in camera) that protrudes from the rear of the lens, while observing the aperture blades, as you apply gentle pressure and release it, the aperture blades should move quickly and freely. If not, the lens aperture is sticking.
Checking camera settings in your posted problem photos, there are 3 different exposures in four photos making a diagnosis from consistant results impossible.
The best way to diagnose this, is set up a controlled test, perhaps a still life using bright controlled lighting, some desk lamps for example so lighting remains the same throughout the test. Using the lens that gives good exposures on the D50, shoot test shots properly exposed with the D50, then using the exact same camera settings, take test shots with the D40. Repeat the process w/the D40 lens, assuming as i said, different lenses on each camera. If both lenses give good results on the D50 and dark results on the D40 then its a camera issue, possibly settings as i mentioned earlier, or a camera fault. If one lens gives consistant good results, and the other consistant bad results on both bodies, its a lens issue.
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the photos were taken with the same lens 18-55mm F3.5-5.6 switching from D40 to D50 within a few minutes so that the light condition was practically the same. The two dark ones was with D40. I'm going to check the lens aperture as you recommended.
I did as you recommended, but could not see any action of the aperture blade. The same on the D50, nothing happens when pressing the lever. Did I do it correctly with the right lever? I don't see anything else.
According to the Exif data Image 2 D40: ISO 200, 1/320th sec. @ f/9, compared to Image 4 D50: ISO 200, 1/250th sec. @ f/8 which is only 2/3rds of a stop difference. 0EV Exposure Compensation in both. Assuming the lighting didn't change dramatically it doesn't add up.
If the Aperture is stuck in the stopped down position, the viewfinder would be very very dark. Again assuming that is not the problem, I suspect a bent stop down lever on the lens or bent actuator on the camera. If the your 18-55mm works correctly on your D50 that would point to a bent actuator on the camera. If your 18-55mm produces dark images on your D50, the stop-down lever on the lens is probably bent causing the aperture to close more than it is supposed to.
Try another lens on your D40 and see if the problem persists. Good Luck and Enjoy your Nikons!
Thu 03-May-12 06:25 AM | edited Thu 03-May-12 06:27 AM by MEMcD
Since the 18-55mm works well on your D50, try another lens on your D40. If the images are still dark, the likely cause is a bent stop dowm actuator in the camera causing the aperture to stop down more than it should. With your 18-55mm again, try Aperture (A) priority mode and set the Aperture to f/22. Is the image still dark? Good Luck and Enjoy your Nikons!
With 18-55mm again, Aperture (A) priority mode and set the Aperture to f/22. The image is not dark but it takes 2 sec for the aperture to snap back (close) and another 1-2 sec for the image to be recorded to the SD card.
The long aperture time causes of course blurring if not on a tripod. The issue is start underexposure, I believe. It can be corrected with high EV setting or low aperture but bound to blurriness if not using tripod.
>With 18-55mm again, Aperture (A) priority mode and set the >Aperture to f/22. The image is not dark but it takes 2 sec for >the aperture to snap back (close) and another 1-2 sec for the >image to be recorded to the SD card.
I suspect the 2 sec. delay is the result of the camera setting a slow shutter speed of about 2 seconds. If you have Long Exposure noise reduction turned on, the camera will capture a second image with the shutter closed and use it to reduce the noise.
>The long aperture time causes of course blurring if not on a >tripod.
The small aperture is causing the camera to use a very slow shutter speed resulting in a blurry image. Since the image is not dark when the aperture is fully stopped down, this would confirm the issue is the stop down mechanism on the camera or lens. You have said that your lens works perfectly on your D50 so the problem is the Aperture Stop down actuator in your D40.
>The issue is start underexposure, I believe. It can be >corrected with high EV setting or low aperture but bound to >blurriness if not using tripod.
For some reason the aperture is stopping down more than it should causing the dark images. What is strange is the first shot is ok and the images get progressively darker with each additional capture. If the stop down actuator was bent, all of the images should be dark. Good Luck and Enjoy your Nikons!
The only way to find out how much it will cost to repair is to send the lens to Nikon Service or a Nikon Authorizes Service Station and get an estimate. You can then determine if it is worth getting the D40 repaired or if it is time to replace it. Good Luck and Enjoy your Nikons!
>Since the image is not dark when the aperture is fully stopped >down, this would confirm the issue is the stop down mechanism >on the camera or lens. You have said that your lens works >perfectly on your D50 so the problem is the Aperture Stop down >actuator in your D40.
If its the actuator then wouldn't be the photos be consistently dark instead of becoming more and more underexposed?
also, I dont have an exif reader. Could anyone see if the exposure settings for those photos changed as the images got darker? If the change in exposure(aperture/shutter/iso) matches the change in exposure (visually) then that eliminates a few possibilities.
Charlie: nice back yard! but i digress... do you get similar results when you try to shoot in less bright environments such as indoors? have you tried using a different lens on the D40?
I tried with two lenses 18-55mm and 18-70mm with same result. Both lenses work fine on other camera (D50). My ad-hoc solution is taking pix in P mode and set EV to +2 under bright sun light or +3 indoors, of course at the expense of longer shutter time, causing sometimes blurring if not on tripod.