I’m currently running a Canon EOS 90d with a Sigma 17-70mm f/2.8-4.0 lens and I cannot seem to get properly exposed. I’m in a well lit room at f/2.8 with a shutter speed of 1/60 and I’m at ISO 100. The image is almost completely black. If I go full auto it raises my ISO to 2000+ sometimes 6400. User error or bad lens? I did pick the lens up from eBay. Or could it be setting in my camera? I’m running mostly default settings so I don’t know what could be wrong on the camera’s side.
Welcome to the forum,Bailey. Try a different environment such as outside in the sunlight, do you still have a issue? As Gary said put up an image, this will help.
Could you post an image using 2.8, one with 4.0 an then maybe one at f 11 and one stopped down to 22 ? Lets make sure the lens is stopping down properly across the range. I would set the ISO to something like 3200 or so and lock that in so its not full auto, but we do want to see it is giving different exposures at different f stops and exposing correctly. Are you using shutter priority or full manual, if manual where is the exposure meter reading? FYI, ISO 100 is not something you would find usable indoors. I guess it depends on what you define as well lit, but i find 800/ 1600 ISO normally fits indoor lighting to get you to about 1/60 or 1/100 if you have windows with daylight spilling in besides the interior lights and that is wide open at 2.8 pr 4.0. If you need to stop down for depth of field you will be looking at a higher ISO.
Alright. Sorry for the delay in responses. The following pictures are taken at f/2.8, f/4.0, f/11, f/22 respectively: It should be noted that these were taken at about an hour and a half before sunset in a heavily wooded area. ISO was kept at 3200 the whole time and shutter speed was kept at 1/60 the whole time. The first image was slightly over exposed, the second image was just right, the third image was slightly underexposed and the third image was obviously well below 3. I got an 18-55mm canon kit lens brand new to test this out and I'm actually getting even worse exposure than with the sigma. I really hope this is just user error cause I'd hate to spend this much money for an image that's grainier than if I were to take it with my phone.
In the previous response I gave the images didn't load correctly for me. It might just be me, but just in case, I'm providing links to these images. https://imgur.com/Bc9I3cD https://imgur.com/YeAV4u5 https://imgur.com/1AG8xSp https://imgur.com/nA7LERy
Lens appears to be operating properly. Not an ideal image to see depth of field. F2.8 allows 6 times the light in as f22. So if your shutter and ISO stay fixed you would have a wide range of bright/dark exposures across each fstop. To keep the brightness of 2.8 at f22 you would need a 1 sec exposure.
Looks like 1/60 at 2.8 is about right at 3200, so that's a EV rating of 9. You must be in full manual. The camera should be showing you are drastically under exposing the image on those dark images. You need to dial the exposure to the center. You need to decide what is important the f stop, the shutter or the ISO. So if you want to freeze action and have the lens down to f8 for some depth of field, your ISO will have to go up accordingly. If the light doesn't change, those three settings have to balance out to allow the exposure.
I’m mainly looking to do amateur filmmaking with the Canon 90d. It’s a bit disappointing that given the lighting circumstances I’d already have to start sacrificing the quality of my video by ruining my shutter speed or DOF. Should I look at getting a slightly better camera or do you think that I could get much better quality out of this camera? This is literally my first experience with any camera that’s not on my phone so I wouldn’t be surprised if I just suck at using it right now.
I think you need to watch videos and read up on exposure, and using a DSLR for stills and video. ...if you are going to move away from shooting with something besides your phone. The camera is much better than your phone, and if you don't know what you want in an upgrade above the 90d, your just guessing at a better camera, and will still have the same struggles. A better camera sensor may have a bit better performance with noise at high ISO, but you need to figure out how to use the dslr first. Any future upgrade should come after mastering your craft. Depth of field: Phone cameras control these settings mostly for you. Also your 1.8 or 2.5 f stop on the phone is more like f8 on a 35mm sensor. Depth of field is controlled by distance to subject, the aperture you use, and its relation to the sensor size... On a DSLR I would shoot a portrait at around f2 on a 85mm lens and get a nice soft background bokeh. A medium format camera maybe 120mm lens at f4, and If I am shooting on 4x5 inch film that would be maybe 180mm lens at f8 to get a similar effect. The reverse is true for landscape, DSLR: 20mm f22 for a landscape shot with lots of depth of fiend, Medium format 50mm and f32, and 4x5 format would be 90mm lens at f64. So... your very tiny sensor in the camera at f2 or what ever it is has depth of field where larger formats would have very shallow depth or not even have the option of going to an f stop that wide. F stop is a mathematical equation it does not change from camera format to camera format. While you can control the lighting you use for a image or video, adding stobes/LED panels/ shooting outside, etc..... The exposure value for that light will not change, you can shoot with a 500$ camera or a $50k camera the settings do not change. A good illustration of this is using a light meter, in my kitchen at this moment the lighting is an EV of 10.8, so I dialed in 3200 ISO as a starting point. you can see 1/30 will give f8, 1/60 (twice as fast) will need f5.6 because f5.6 allows in twice as much light as f8. and if i double again to 1/125 that takes aperture down to f 4.0. 1/30 is slow enough that you will get motion blur, and f4 is wide enough you will see noticeable background blur on your focused subject. Overhead lighting in a living-room is not really that bright. No mater which camera you have, these numbers are the same! Video is another beast, maybe one of the guys that shoot video can jump in here and advise. What I can say is people that shoot video indoors add addition video lighting panels. Lighting is a craft in and of itself for both stills and video photographers..
Your phone likely only operates in a fstop range between 1.5 and 2.5 which will give you a medium depth of field on that tiny sensor. The soft portrait look is created by machine learning to soften the image by the software, not by the physical lens on your phone.
