Steve Crow
Forum Replies Created
-
So you’re saying while in aperture priority mode the only aperture you can set is a 4.0 and it won’t let you set it to anything else? What happens when you try and select another aperture like 8.0?
Is this a fixed aperture lens by any chance? What lens do you have?
When taking still photographs can you use other apertures besides 4.0?
Steve Crow
-
Not sure I 100 percent got your question but let me take a shot at it, and forgive me if I blow it.
For your filming situation I would set my aperture way more towards the “closed” end because that way you will have a deep depth of field and most everyone in your audience is going to be in focus. F8 or even higher.
I think at first I misunderstood your question and I wanted to point out to you that your exposure and your focus are two separate things. I thought perhaps what you meant was that you were afraid that the some of the audience members would be overexposed or blown out but now I think you were actually talking about Depth of Field issues.
Anywho….unless you set up a professional lighting grid to ensure even lighting throughout the audience area, yes there are going to be different levels of exposure.
What I’m saying is go into manual mode and then pick an exposure that works out the best OVERALL even if some areas are SLIGHTLY over or under exposed. For an F8 aperture, I would expect to have to use a fairly high ISO because 95% of the time I keep my shutter speed at 1/50th or twice my 24fps frame rate.
AV and TV modes are not DOING the same thing in video. In AV mode you are selecting the aperture and the camera is selecting the shutter speed and ISO while in TV (t for “time”) you are selecting the shutter speed and the camera is selecting the aperture and ISO for you. Now, in both cases, the camera will try and work out a combination of settings that gets you an acceptable exposure, somewhere right in the middle between not too dark or too bright, and the resulting shot may very well look exactly the same in terms of overall exposure in both AV and TV modes. The only difference is HOW the camera is achieving that exposure.
But of course, yes, different apertures, shutter speeds and ISO can make a HUGE difference in the overall look of the video – the depth of field, the “smoothness” of the movement and exposure. That’s why I only really shoot in manual mode for my projects, because I want to control all 3. If I were doing fast moving action type stuff yes then I might choose AV or TV mode (most probably AV) but in your case, I’d go manual all the way since it doesn’t sound like the lighting conditions are going to change.
Steve Crow
-
If low light performance is the only issue you are trying solve then I would take a look at the Sony A7s
Its low light performance is really something. There are tons of examples posted online.
Steve Crow
-
I think you are not filming in full manual mode so that the camera is making some auto corrections to the exposure as the overall light conditions change. Set your exposure manually and then leave it alone and I think the problem will go away – let us know if that works for you.
Steve Crow
-
Hey Matt,
I don’t understand how what you describe could be possible, if the exposure is changing then the DOF must be changing too. There has been lots of talk online about the A55 being prone to malfunctions and needing repairs but I’m assuming for the following that everything is actually in working order.
Set up a simple table top test, rest your camera at one end of your family’s dinner table at table top height. Now place a coffee cup or something 1.5 feet in front of of the end of the lens and then set up another group of objects 2 or 3 feet behind the cup.
Put your camera in full manual mode, set the lens so that you are at a 50mm field of view, switch over to video and then focus on the cup with your aperture set at 3.4. Now film. This will give you a very shallow depth of field, in fact some portions of the cup furthest away from you may be out of focus – as by my calculations the area in focus will only be .03 feet – but definitely the second group of object further along the table will be blurred.
Steve Crow
-
I am not expert in this area and it may seem rather obvious but have you dug through the conversion/output options to see if you can turn off the broadcast safe feature which is what I think you are describing?
Steve Crow
-
A couple of things come to mind:
* Your shutter speed should be approximately 2x your frame rate so in your case that would be a shutter speed of 120 or as close as you can come to that. You are at 300 so I would expect to see some jerkiness in your final video
* Regarding 60p; yes they may have very well set their camera to 60p in order to get a slow motion effect. However, that doesn’t mean they OUTPUT the final video at 60p. In fact to get the slow motion effect they would have to output the final video at something more like 24p from their editing system.
* Try a shutter speed of 1/50 and a setting of 24fps per second instead for normal footage and save the 60fps for your slow motion shots only.
Steve Crow
-
My first thought would be to continue on with the flat picture style you are using for this one project specifically and THEN when you’re ready to start a new project take another look and decide if you want to continue in that mode or to select another picture style.
This way everything for this project will remain with the same basic look making your job in editing a bit easier as you can develop custom “looks” in your editing program and apply those to whatever clips you want. If you are mixing up two different picture profiles, it will take a bit more work. With the experience of editing your film behind you, you will be in a much better position to decide what kind of picture profile you want to use moving forward.
By shooting flat you are not giving up anything and is maybe a good compromise between RAW and selecting a baked-in picture profile look from the many available to you.
Steve Crow
-
I am not sure if I am completely understanding the problem but if you were using some kind of automatic focus tracking (face tracking for instance) and then stepped out of the scene to go behind the camera, then the camera’s software would probably get very confused on what it should focus on next.
Perhaps try setting a manual focus point with a relatively closed off aperture so that no matter where you move in your chair, forward or backwards or sidewise you will remain in focus. Something like a F8 should definitely do it but you may be able to stop down a stop too – you will have to check your focus distance given the focal length and aperture.
A higher aperture means more light will be required or you will have to raise your ISO to compensate.
If you want a shallow depth of field then you can still pre set a manual focus point but of course you will have to remain much more still in your chair while recording and be more precise in setting your focus point. I hope this all makes some sense to you and is helpful.
Steve Crow
-
Yeah, I have to agree with the other poster that DSLR is not the best camera platform for what you’ve described. A DSLR would be great for interviews, b-rolls, behind the scenes stuff but not for recording long lectures where often the camera is locked down and there’s not a lot of re-framing, re-focusing etc going on.
DSLR video has a much better look of course but maybe for your peace of mind go with a more traditional video camera body. Some of them do offer full manual control but at the $1,000 or below price point I wouldn’t expect it to be too great on that front and yes, fixed lens is probably what you are looking at too. Renting could get you access to these more advanced cameras that are a combination of DSLR sized sensors, interchangeable lenses, built in audio and ND features – all combined in a traditional videocamera form factor.
All the DSLR cameras have some sort of time and/or file size limitations – my understanding is that the Panasonic GH4 models have a longer one than the 12 minute / 4GB limit I used to with my Canon T2i.
Because there aren’t any opportunities for “do overs” and “second takes” in your shooting situation, I’d feel most comfortable recommending you go with the most simple and reliable solution – and with color grading, smart lighting and some careful editing you might still be able to get an image approximating a DSLR look – minus the shallow depth of field unless you are way way back.
Now I go back a few years and I remember when the craze was outfitting a Canon HV20 (a very basic video camera) with a gizmo called a Depth of Field adapter from Red Rock Micro (the M2) that went in front of the Canon lens and gave you a much more cinematic shallow DOF look out of a very consumer camera. It might be interesting to see where that technology evolved to.
Steve Crow