I recently purchased a Nikon D610 with a 50mm lens. I also have a D5200 with Sigma 18-250 lens. I used to shoot softball games with the 5200 on Manual mode at about 1250 F5.6 ISO 100 and get good shots. This past weekend I put the Sigma on the D610 and the only way I was able to get decent exposed shots was by lowering the Shutter speed to a speed that was not able to totally freeze the action. Is there any reason that the exposure of the images would be different on the two cameras using the same lens?
There are several things that could be going on here to cause what you are describing:
- Not all daylight is equal. Time of day and time of year both affect the angle of the sun in the sky which affects how much of the sun's energy is falling on a specific amount of area, cloud cover affects how much of the sunlight reaches the ground, and even how much moisture and particulates in the air can affect overall brightness. Then there is the entire issue on a bright sunny day of which parts of the field are in direct sunlight and which parts might be in shade. The exposure values needed for each are several stops apart. Even in Manual exposure mode, metering is important! So is the Exposure Compensation setting for cameras that allow EC in M exposure mode with Auto ISO.
- The mechanical aperture lever on Nikon cameras is prone to being damaged if a lens is improperly positioned while being mounted. If the lever gets bent it will affect the actual versus selected aperture value for each shot.
- In-camera settings such as Auto ISO (and for those shooting Canon and some other camera brands - Safety Shift) can alter manually entered aperture and shutter values when set to enabled if the camera detects the scene is out of range for the selected settings.
- Different metering modes interpret the same scene differently, especially scenes in which some areas are much lighter or darker than others. That's why it is important to know the metering mode to which you have the camera set and how that affects the scene you see in your viewfinder.
- There are multiple versions of the Sigma 18-250mm lens, but all of them have a maximum aperture of f/6.3 on the long end. This means neither of your cameras can use f/5.6 when the lens is zoomed past a certain focal length. Depending on camera settings, the camera may still use the selected ISO and shutter time or it may compensate for the dimmer aperture. Check to see if the similar settings are the same for both the D610 and the D5200.
- The Sigma 18-250mm are also DX lenses, which means your D610 is shifting to crop mode and only using the center 45% of the imaging sensor. This may also be affecting metering decisions if Auto ISO (with or without EC) is enabled.
If you check the EXIF info of your previous shots with the D5200 and your more recent shots with the D610 I expect that you will find the D5200 was bumping up the ISO to compensate for the narrower maximum aperture and the D610 was not, forcing you to increase the shutter time.
A camera set at ISO = 100, f5.6, and 1/1250 has an EV_100 value of 15.333 and will be about 1/3 stop over exposed for a normal scene in full sunlight. However it will be under exposed by 0.67 stops in hazy conditions and 2.67 stops under exposed during heavily overcast daylight conditions. For night sports, it will be about six stops underexposed.
It's worth noting that the EV_100 scenes for daylight conditions assume that the shots are not taking place near the Earth's poles where the sunlight will tend to be less intense than nearer the equator.
Should there be a difference between the D5200 and the D610? Well it depends on your perspective.
No camera with manual settings of f5.6, ISO 100, 1/1250 should produce consistent proper exposure under variable daylight conditions. As cloud shadows move across a softball field the shots should become under exposed.
If you are getting consistently good exposure as the light varies in intensity, then the D5200 is perhaps doing what you meant rather than what you said. That it was producing pleasing images, explains why a camera manufacturer might ignore manual settings on an entry level camera.
Of course the difference in camera performance could be down to lower levels of light for the shots taken with the D610. Again, It can be as much as three stops in daylight and six stops for a night game.
Raise the ISO instead of lowering the shutter speed. Contemporary DSLR's often shoot surprisingly well at ISO ratings that would cause great concern when shooting with film. Because digital noise is not equivalent to film grain, it does not degrade an image in the same way (and not as severely for most viewers).
Allowing the camera to vary ISO from 100 to 800 or 1600 or 3200 to allow the camera to adjust exposure for varying light conditions often works for when I shoot daylight sports.
Make sure the D610 is not using any exposure compensation. If it is, reset it to zero.
Cameras vary in terms of exposure analysis. Switching to program mode and taking a test shot is a good way to measure light in a scene and then to dial in an equivalent EV_100 setting. Matrix metering in program mode will provide insight into the overall scene illumination. Adjusting to spot metering in program mode will provide insight regarding proper exposure for specific elements such as skin tones or uniforms.
Developing a habit of reviewing shots in camera by looking at the histogram provides quick feedback. Settings can be adjusted during a game to improve the next image.