What's the limit for maximum DOF?

[RieniO]

Most of you probably like the GH1 for it's small DOF, but what if you want to maximize DOF? I am shooting indoors with 3 fluorescent lights, last time I shot at ISO 400 and 1/50s, and I wish DOF would have been a bit larger. Would I get myself into trouble by shooting at ISO 800 and/or 1/30s ? I shoot in PAL FHD AVCHD.

 

[e-steve]

DOF has little to nothing to do with your shutter speed or ISO settings. The best thing to do is google some info on it to learn what factors affect DOF, so you can make your adjustments based on your understanding of DOF.

http://photo-class.deviantart.com/art/Understanding-Depth-of-Field-6247785

http://www.dpreview.com/learn/?/key=depth+of+field

http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

Basically the key factors for adjust DOF will be focal length (zoom), subject distance from background, subject distance from camera, and the aperture (the lower the number the shallower the DOF).

Among the biggest reasons "fast" lenses are sought after and are more expensive is their ability to shoot at a locked aperture setting, which allows for greater flexibility for DOF adjustments, as well as low light shooting (the smaller the aperture number, the less light you need also).

Good luck!

 

[RieniO]

shutter speed or ISO settings have everything to do with DOF. As you write yourself; "aperture (the lower the number the shallower the DOF)". Now the longer the shutter speed and the higher the ISO, the smaller the aperture (higher number, for example F8) can be set, thus the higher the DOF. When posting my question I was assuming all this are established facts and didn't have to be explained

 

[PerroneFord]

shutter speed or ISO settings have everything to do with DOF. As you write yourself; "aperture (the lower the number the shallower the DOF)". Now the longer the shutter speed and the higher the ISO, the smaller the aperture (higher number, for example F8) can be set, thus the higher the DOF. When posting my question I was assuming all this are established facts and didn't have to be explained

What in the world are you talking about?

ISO and Shutter speed have exactly ZERO to do with DOF. They have EVERYTHING to do with how to make a correct exposure when you've selected the DOF you want, but that is a totally different concept.

DOF control is a factor of:

1. Subject to camera distance
2. Focal length of the lens
3. Selected Aperture.

Once these three items are controlled, you can then make adjustments on the camera (not the lens) to gain correct exposure for the DOF you'd like to have.

In the film world, ISO and Shutter speed are FIXED so the only adjustments to DOF that are possible are with the factors just mentioned.

In fact, if you frame a shot, and are happy with the DOF, then change either ISO or shutter speed, your DOF won't change one bit. EVER. Your exposure density will simply change.

 

[PerroneFord]

Most of you probably like the GH1 for it's small DOF, but what if you want to maximize DOF? I am shooting indoors with 3 fluorescent lights, last time I shot at ISO 400 and 1/50s, and I wish DOF would have been a bit larger. Would I get myself into trouble by shooting at ISO 800 and/or 1/30s ? I shoot in PAL FHD AVCHD.

This comment explains that you have no understanding of DOF or rudimentary photography. If you want a larger depth of field, you reduce the ISO to perhaps 100, then stop the lens down to compensate exposure, thus increasing depth of field. Going to ISO 800 is exactly the opposite choice one should make.

 

[Nitsuj]

I can only suggest going to a book store and picking up a book on photography and filmmaking ("The Filmmakers Handbook" is an excellent choice) and go from there. It isn't a good idea to learn about the basics on a forum because there is just too much to learn and most people don't have the time to explain everything that is already available in books. I would suggest taking notes on everything and then take them with you as you practice.

 

[thisisapocalypse]

This comment explains that you have no understanding of DOF or rudimentary photography. If you want a larger depth of field, you reduce the ISO to perhaps 100, then stop the lens down to compensate exposure, thus increasing depth of field. Going to ISO 800 is exactly the opposite choice one should make.

What?

To increase the depth of field, you need more light in order to maintain proper exposure, because more than likely you are going to have to stop down your lens.

So you either add more lights, up the sensitivity of your film (in this case digital), and/or use a longer shutter speed in order to compensate for the stopped down lens.

 

[PerroneFord]

What?

To increase the depth of field, you need more light in order to maintain proper exposure, because more than likely you are going to have to stop down your lens.

So you either add more lights, up the sensitivity of your film (in this case digital), and/or use a longer shutter speed in order to compensate for the stopped down lens.

DOH!

I shouldn't post when frustrated...

Fundamental is this:

1. Stop down the lens to get desired look
2. Adjust ISO/Shutter speed to correct exposure

Sorry.

 

[thisisapocalypse]

ISO and Shutter speed have exactly ZERO to do with DOF.

I think this is a bit of an extreme thing to say. In a purely technical/abstract sense it's correct...I guess, but I don't think it matters because you can't create an image without a shutter speed and without a film speed.

Your available film/iso speeds, desired shutter speed, and lighting conditions are going to give you a set of parameters for your your aperture with which you must work within, in order to get proper exposure, all of these things are tied together pretty closely.

 

[PerroneFord]

I think this is a bit of an extreme thing to say. In a purely technical/abstract sense it's correct...I guess, but I don't think it matters because you can't create an image without a shutter speed and without a film speed.

Your available film/iso speeds, desired shutter speed, and lighting conditions are going to give you a set of parameters for your your aperture with which you must work within, in order to get proper exposure, all of these things are tied together pretty closely.

Tied together? Sure. But for the purposes of explaining DOF? No.

If my chosen lighting conditikons allow me a 1/48 shutter at F4 and my ISO is 400, and I want more DOF, I can change the ISO to 200 or 800 and my DOF won't change at all. I can alternately change my shutter speed to 1/24 or 1/100 and my DOF won't change at all. What will change is that I will over or under expose by a stop.

If you absolutely, positively have to increase DOF then underexposing by 1 stop may well be an acceptable tradeoff.

To make a correct exposure (which is different than varying the DOF) you have these factors

1. Focal length. Go to a wider lens with the same exposure settings.
2. Subject to camera distance. Move closer and keep everything else the same.
3. Decrease aperature (and lose light, adjust light, change ISO, change shutter)

If you know of another method to adjust DOF please let me know.

 

[RieniO]

Yeah right

This comment explains that you have no understanding of DOF or rudimentary photography. If you want a larger depth of field, you reduce the ISO to perhaps 100, then stop the lens down to compensate exposure, thus increasing depth of field. Going to ISO 800 is exactly the opposite choice one should make.

 

[e-steve]

I think probably your understanding of DOF was misunderstood by the original wording of your question. Having gone back to read it, the question might better be stated:

"If I want to shoot at the highest possible aperture (for max DOF), what is the highest ISO and the slowest shutter speed I can get away with?"

I would say you can probably will be fine going up to ISO 1600 or just 1000, but the 1/30 shutter will make your shot have a lot of motion blur.


Whether you get into trouble will depend really on if you have done your chores for the day and if your mom and dad are in a good mood or not.

 

[RieniO]

Your available film/iso speeds, desired shutter speed, and lighting conditions are going to give you a set of parameters for your your aperture with which you must work within, in order to get proper exposure, all of these things are tied together pretty closely.

Yes and if your lighting conditions are not changeable, and you have correct exposure but not enough DOF, you slow down your shutter speed and increase ISO so you first get overexposure, which you correct by closing down your aperture a few steps resulting in correct exposure and larger DOF. What the f*ck am I talking about, I need to read a few books!!!!!!!!!!

 

[thisisapocalypse]

Yes and if your lighting conditions are not changeable, and you have correct exposure but not enough DOF, you slow down your shutter speed and increase ISO so you first get overexposure, which you correct by closing down your aperture a few steps resulting in correct exposure and larger DOF. What the f*ck am I talking about, I need to read a few books!!!!!!!!!!

I dunno, you sound like you get it to me...or are you saying that you understand this in theory but don't have a good grasp yet of the terminology in a practical sense?

Either way, it will come in time, this stuff really isn't all that difficult and honestly just spending some time with your camera and shooting, trying different things out, etc., will teach you a lot pretty quickly...

Cameras and photography are wonderfully simple and tremendously complex at the same time. All that really happens as you get better (assuming you are good at composition and telling the stories you want to tell) is that you learn how to "think" about your approach to the technical side more quickly (and after a while it almost becomes as natural as any bodily function), gain experience from your failures and successes so that you have more successes going forward.

But, at least in terms of using the camera, the only things we can screw up are focus, shutter, aperture, and film speed. Could be worse! Of course, composition can be infinitely screwed up. But that's not what we're talking about

 

[RieniO]

I would say you can probably will be fine going up to ISO 1600 or just 1000, but the 1/30 shutter will make your shot have a lot of motion blur.

I agree on the 1/30s blur, especially because I am shooting handheld a lot. But some claim it's better not to go above ISO400 and I don't know why that is. I would love to shoot at ISO1600 but apart from extra noise, are there other problems?

I did bookmark your links by the way so you didn't waste your time
Here's another cool link about DOF, the online depth of field calculator. The GH1 is also listed:

http://www.dofmaster.com/dofjs.html

 

[RieniO]

I dunno, you sound like you get it to me...or are you saying that you understand this in theory but don't have a good grasp yet of the terminology in a practical sense?

Nah I do get it and was just being sarcastic about having to read books, but I should have ignored the personal comments. Back to topic; it's just as you wrote, everything is linked together, you can't change one thing without influencing everything else.

 

[Nitsuj]

Nah I do get it and was just being sarcastic about having to read books, but I should have ignored the personal comments. Back to topic; it's just as you wrote, everything is linked together, you can't change one thing without influencing everything else.

Being snarky gets you nowhere but I will explain what is readily available in a book AND already on these forums. To increase the depth of field you need to stop down, use a wide-angle lens, or move further away from the subject. Yes stopping down decreases light and you would need to compensate by putting more light on the subject or increasing the ISO. When you asked about if you would "get in trouble" it is hard to determine exactly what that trouble really is in your situation which you did not describe. So anybody reading it could only assume that you mean degrading picture quality. So yes you would degrade quality the further you push the ISO. It's been tested and tried many times in this forum that the GH1's safe zone is 100 - 400 ISO and anything after that will start to show noticeable degradation. Of course this can also depend on what the final output is going to be. If it was going to be shown on a tiny square onto a web page than pushing up to 800 ISO can be okay since the quality will most likely be pushed way down anyway due to heavy compression. As far as shutter goes that would only be a personal taste of what is acceptable in your eyes. So with all that being said I would suggest getting a different lens if you want to increase DOF within the limiting factors you are stating or get some more lights. Suggesting to pick up a book and reference this information is not a "personal" insult. The information in books and what is already available for reading in these forums would have answered this question and probably been more thorough. There are countless times when somebody comes in asking basics that could be better explained in a book, class, or both. Enjoy and have fun reading. :thumbsup:

 

[John Caballero]

We are in the era where anybody picks up a camera and is an instant "photographer" or "cinematographer". You really need to read books, (even the "FOR DUMMIES" series!) or the proper info in the internet to after many many years really become a knowledgeable pro. You can also go to school, or work with pros in the field. Misinformation and incorrect information can do permanent damage to the brain!

BTW: DOF is not that difficult to understand.

1- Deep focus or very sharp back and front DOF: wide angle and close the f/stop as much as possible.
2- Shallow DOF: Open the f/stop wide, zoom in, or use a long focal length prime lens.

I don't know how some people make some things to be so scientific.

ISO becomes irrelevant when you know that you can use ND filters to reduce exposure and allow you to use wider apertures if you have too much available light.

 

[e-steve]

I was only giving some links on how DOF works because sometimes we can think that one setting is the key and if we just understood how it works a little we can make better decisions on what to adjust. I've gone for a year before not understanding the way something works, and then once I took the time to learn it it was so much clearer to me.

I think the OP actually understands it, but his initial wording of his question made me think he didn't understand the most important variables. He was really just asking what acceptable ISO and shutter speeds are (the true answer to this is just "it depends")

 

[RieniO]

Yes stopping down decreases light and you would need to compensate by putting more light on the subject or increasing the ISO.

Ok this was my point.

When you asked about if you would "get in trouble" it is hard to determine exactly what that trouble really is in your situation which you did not describe. So anybody reading it could only assume that you mean degrading picture quality. So yes you would degrade quality the further you push the ISO. It's been tested and tried many times in this forum that the GH1's safe zone is 100 - 400 ISO and anything after that will start to show noticeable degradation. Of course this can also depend on what the final output is going to be. If it was going to be shown on a tiny square onto a web page than pushing up to 800 ISO can be okay since the quality will most likely be pushed way down anyway due to heavy compression.

I mainly distribute through web streaming in 960 x 540 resolution but in the near future when technology enables faster streaming, the market will demand full HD resolution of course, and I want to be prepared for that. So I guess I'll need to stick with ISO 400 then.

As far as shutter goes that would only be a personal taste of what is acceptable in your eyes. So with all that being said I would suggest getting a different lens if you want to increase DOF within the limiting factors you are stating or get some more lights.

I plan to buy more lights, yes. Am wondering how the new LED lamps compare to fluorescent lights.