Does dof have to suffer because of low light.

oakfieldphotography.comoakfieldphotography.com Registered Users Posts: 376 Major grins
edited May 9, 2011 in Cameras
Hi everyone
I was just curious to know does my dept of field have to suffer if i am working in dull light. It is just that when i take pictures of vintage and classic cars comming towards me on cloudy dull days the headlamps are out of focus and the rest of the car is sharp. I do struggle with my camera on manual mode but i cant seem to find the shutter speed on dull days to keep those lamps sharp. I am using a 5d2 and a canon f1.8 lens.

Regards
Pat:D

Comments

  • ThatCanonGuyThatCanonGuy Registered Users Posts: 1,778 Major grins
    edited May 7, 2011
    DOF does not suffer with low light. If you use a larger f/stop (say, 1.8) vs a smaller one (say, 5.6), you get more DOF. With low light, you want to use larger f/stops (smaller numbers). That's part of the reason that the 400mm 2.8 II is about 11 times the price of the 400 5.6 (11,000 vs ~1,000).

    Do you mean the headlights aren't in focus, but the rest, including the back, sides, and front, is? That's probably the light diffusing in the rain/fog or something? If the headlights are OOF (out of focus), then the rest of the front should be as well.

    Oh, you want less DOF? That makes sense. Well, even at f/1.8, I don't think the headlights would be OOF and the rrest of the front of the car would. I'd like to see some examples deal.gif
  • oakfieldphotography.comoakfieldphotography.com Registered Users Posts: 376 Major grins
    edited May 7, 2011
    ThatCanonGuy wrote: »
    DOF does not suffer with low light. If you use a larger f/stop (say, 1.8) vs a smaller one (say, 5.6), you get more DOF. With low light, you want to use larger f/stops (smaller numbers). That's part of the reason that the 400mm 2.8 II is about 11 times the price of the 400 5.6 (11,000 vs ~1,000).

    Do you mean the headlights aren't in focus, but the rest, including the back, sides, and front, is? That's probably the light diffusing in the rain/fog or something? If the headlights are OOF (out of focus), then the rest of the front should be as well.

    Oh, you want less DOF? That makes sense. Well, even at f/1.8, I don't think the headlights would be OOF and the rrest of the front of the car would. I'd like to see some examples deal.gif

    I am just about to go out soon to take pictures of the Mini Owners Club of Irelands road trip from Mitzen in Cork to Mallin Head in Donegal. I am hooking up with them in North Leitrim and i will post some pictures Late tonight or tomorrow. You will see what i mean as soon as i post some pictures here. I probably should be using AI Focus or i will try AI servo which ever is the best for cars coming towards my lens. I am trying to capture the landscape in the background as well. I know that the 5d2 is slow to focus but i will try my best. Any tips?
    Regards
    Patrick:D
  • ziggy53ziggy53 Super Moderators Posts: 24,129 moderator
    edited May 7, 2011
    ThatCanonGuy wrote: »
    DOF does not suffer with low light. If you use a larger f/stop (say, 1.8) vs a smaller one (say, 5.6), you get more DOF. ...

    Just the opposite is true. Larger apertures, for instance the f1.8, produced "limited" DOF. Smaller apertures, bigger numbers like f5.6, produce "deeper" or "extended" DOF.

    Here is example showing, from top to bottom, limited through extended DOF:

    http://www.wildlife-photography-tips.com/images/dofEg.jpg
    ziggy53
    Moderator of the Cameras and Accessories forums
  • ziggy53ziggy53 Super Moderators Posts: 24,129 moderator
    edited May 7, 2011
    oakfieldphotography.com wrote: »
    Hi everyone
    I was just curious to know does my dept of field have to suffer if i am working in dull light. It is just that when i take pictures of vintage and classic cars comming towards me on cloudy dull days the headlamps are out of focus and the rest of the car is sharp. I do struggle with my camera on manual mode but i cant seem to find the shutter speed on dull days to keep those lamps sharp. I am using a 5d2 and a canon f1.8 lens.

    Regards
    Pat:D

    In low light one tends to use larger apertures in order to allow either lower ISO or higher shutter speeds. If you need more DOF you must choose a smaller aperture. In order to maintain the same exposure that means either you need a higher ISO or a longer shutter speed, or some combination thereof. Usually subject motion or camera motion will determine the need for a particular shutter speed, leaving ISO as the only variable.

    It is always a challenge to try to maintain proper exposure, but like all challenges it can be both frustrating and rewarding. clap.gif
    ziggy53
    Moderator of the Cameras and Accessories forums
  • ziggy53ziggy53 Super Moderators Posts: 24,129 moderator
    edited May 7, 2011
    oakfieldphotography.com wrote: »
    I am just about to go out soon to take pictures of the Mini Owners Club of Irelands road trip from Mitzen in Cork to Mallin Head in Donegal. I am hooking up with them in North Leitrim and i will post some pictures Late tonight or tomorrow. You will see what i mean as soon as i post some pictures here. ...

    Please do post some images of the problem. I suspect that you are running into an issue with dynamic range of the scene and lens flare.
    oakfieldphotography.com wrote: »
    ... I probably should be using AI Focus or i will try AI servo which ever is the best for cars coming towards my lens. I am trying to capture the landscape in the background as well. I know that the 5d2 is slow to focus but i will try my best. Any tips?
    Regards
    Patrick:D

    AI-Servo is best for moving subjects, or for when the subject is moving with relation to the camera (as in when "you" are moving but the subject is either in opposing motion or still.)

    AI-Focus is not another mode of focus operation. AI-Focus means that you are allowing the camera to choose between AI-Servo and One-Shot focus modes. Never trust the camera to make the right decision.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • oakfieldphotography.comoakfieldphotography.com Registered Users Posts: 376 Major grins
    edited May 7, 2011
    ziggy53 wrote: »
    In low light one tends to use larger apertures in order to allow either lower ISO or higher shutter speeds. If you need more DOF you must choose a smaller aperture. In order to maintain the same exposure that means either you need a higher ISO or a longer shutter speed, or some combination thereof. Usually subject motion or camera motion will determine the need for a particular shutter speed, leaving ISO as the only variable.

    It is always a challenge to try to maintain proper exposure, but like all challenges it can be both frustrating and rewarding. clap.gif

    Thanks Ziggy53. This is the constant battle i get into with my camera since i want to shoot in Manual mode. I thought at one stage that if i pressed the iso button on top of the camera that i was looking at the exposure the camera was taking the picture at but it looks like it was the control for my level of power i want my oncamera flashunit to work at.
    It is definatly hard concerning Manual mode when i want to lock the exposure. Can the 5d2 display the exposure level before you take the picture as the light meter is confusing as it jumps up and down. Or can i lock exposure for a series of shots whilst using manual mode?

    Thanks ziggy, much appreciated.
    Regards
    Patrick:D
  • ziggy53ziggy53 Super Moderators Posts: 24,129 moderator
    edited May 7, 2011
    oakfieldphotography.com wrote: »
    Thanks Ziggy53. This is the constant battle i get into with my camera since i want to shoot in Manual mode. I thought at one stage that if i pressed the iso button on top of the camera that i was looking at the exposure the camera was taking the picture at but it looks like it was the control for my level of power i want my oncamera flashunit to work at.
    It is definatly hard concerning Manual mode when i want to lock the exposure. Can the 5d2 display the exposure level before you take the picture as the light meter is confusing as it jumps up and down. Or can i lock exposure for a series of shots whilst using manual mode?

    Thanks ziggy, much appreciated.
    Regards
    Patrick:D

    The short answer is that everything will improve as you gain experience with the camera.

    There is no single answer to the question of exposure. There is nothing I can tell you that works in every situation. You need to practice more with the camera and practice using the different exposure settings to understand what the settings mean for your photography and how to choose which settings and for what situations. Practical experience is what will allow you to advance more than anything I can say.

    It can take years to gain this experience to a point that you can really feel comfortable about your choices. There will still be times when you question yourself and even times when you mess up. It's all part of the process. Make sure to give yourself this time to grow with your camera and don't beat yourself up when things don't go perfectly.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • puzzledpaulpuzzledpaul Registered Users Posts: 1,621 Major grins
    edited May 7, 2011
    For your situation - subject coming towards me - I'd use either M or Av mode, AIservo, single focus point (manually selected)
    Choice of M/Av would be related to big changes (or not) in overall exposure conditions eg tracking a bird with vastly differing backgrounds, or just across a (constant) sky.

    I don't see any mention of what focal length your 1.8 lens is - there'll be a considerable difference in dof between a 50mm and a 200mm ... should you be fortunate enough to have one of the latter :)

    pp

    edit
    If circumstances allow, I also take test shots and review the histogram.
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  • chrisjohnsonchrisjohnson Registered Users Posts: 772 Major grins
    edited May 7, 2011
    Ziggy is spot-on. Could also be you are a bit too close to the car. Check the DOF tables for the lens you are using - www.dofmaster.com helps and otherwise Canon publish tables. With a moving object you will need a generous range of sharpness.

    I doubt this is related to your focus technique; AI servo is best for a consistently moving object like a car but you still need enough DOF to get everything sharp, especially when the background also has to be sharp. Perhaps you should use the lens on "infinity" and figure out how far away you need to be.

    The DOF has nothing to do with poor light as such. However, to get a big DOF you usually need a small aperture and this can be challenging when you also need a fast shutter. The 5D Mk2 gives a lot of flexibility with ISO so perhaps you should start shooting with max ISO and work backwards from there until you find the right balance.
  • oakfieldphotography.comoakfieldphotography.com Registered Users Posts: 376 Major grins
    edited May 7, 2011
    Thanks Ziggy and Paul.
    I guess i will have to travel down this road. Case closed until i post some pictures of this event for closer scrutiny.Thanks again lads your help is invaluable to me.wings.gif

    Regards
    Patrick.
  • divamumdivamum Registered Users Posts: 9,021 Major grins
    edited May 7, 2011
    The relationship between poor light and dof is that the less light you have to work with, the more you are likely to open up the aperture to get a decent exposure.... thus shallower depth of field. This could easily result in part of the car being sharp and part of blurring away, depending on your distance from the subject.

    The ISO button increases the sensitivity of the "film" (in this case the sensor) to light, thus higher ISO for lower light. On the 5dII you can comfortably go up to iso 3200 and still get great, virtually noise-free shots (even 6400 is pretty good on the 5dii) - push that ISO up, and then you can stop down the lens to get a bit more dof.
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  • ImageX PhotographyImageX Photography Registered Users Posts: 528 Major grins
    edited May 7, 2011
    oakfieldphotography.com wrote: »
    Thanks Ziggy53. This is the constant battle i get into with my camera since i want to shoot in Manual mode. I thought at one stage that if i pressed the iso button on top of the camera that i was looking at the exposure the camera was taking the picture at but it looks like it was the control for my level of power i want my oncamera flashunit to work at.
    It is definatly hard concerning Manual mode when i want to lock the exposure. Can the 5d2 display the exposure level before you take the picture as the light meter is confusing as it jumps up and down. Or can i lock exposure for a series of shots whilst using manual mode?

    Thanks ziggy, much appreciated.
    Regards
    Patrick:D

    If you want an easy way to learn to shoot manual... shoot in auto mode.mwink.gif Basically, your camera is very smart and knows how to get a proper exposure. Take a pic in auto and look at what settings the camera chooses. Then go into manual mode and adjust from those very settings. Of course the camera does not know exactly what the photographer wants as far as creativity, DOF, and other dynamics. That is up to you but you can adjust from the camera's baseline settings and it will get you there faster in most cases.

    You definitely need to shoot MOVING subjects in continuous servo or whatever it's called on Canon... especially if the subject is moving towards or away from you.

    Your original question has been answered but you will always lose DOF when opening up your aperture.... and gain DOF when stopping it down. A quick example is opening your own eyes as wide as you can. Not much in focus, huh? Now squint them and everything comes in focus. Also try that looking at the cars coming at you. It's all the same thing. Eyes, lens... whatever. Open wide = less focus. Close down= more focus
  • ThatCanonGuyThatCanonGuy Registered Users Posts: 1,778 Major grins
    edited May 7, 2011
    ziggy53 wrote: »
    Just the opposite is true. Larger apertures, for instance the f1.8, produced "limited" DOF. Smaller apertures, bigger numbers like f5.6, produce "deeper" or "extended" DOF.

    Here is example showing, from top to bottom, limited through extended DOF:

    http://www.wildlife-photography-tips.com/images/dofEg.jpg


    Yeah, FSR I was thinking he was going for less DOF. Then I realized (hence the "Oh,..." to start my last paragraph) that he wanted more DOF. And by "greater" I meant creamier bokeh, I just messed up ne_nau.gif
  • oakfieldphotography.comoakfieldphotography.com Registered Users Posts: 376 Major grins
    edited May 9, 2011
    Hi all
    I am just recovering from a very hectic weekend and came up with a few shots. I think i am happier now that i mostly shoot in manual now since Ziggy said it was going to be a long learning curve. I did not have any trouble with the cars headlights since and would like to thank everyone here for their help.
    Have a look and see what you think
    5704027198_dbfb9338b2_z.jpg
    Ansel Adams never had a Mini. by OakField Photography, on Flickr

    5703804228_e3aebdf8d4_z.jpg
    Mini Estate by OakField Photography, on Flickr

    5703457155_cec8f45f8f_z.jpg
    At Last. by OakField Photography, on Flickr

    5704025076_b2edb1e1bf_z.jpg
    Mini Adventure by OakField Photography, on Flickr
    5701887714_22c85ae475_z.jpg


    Mizen to Malin 2011. by OakField Photography, on Flickr

    5703867138_fe6b651c72_z.jpg
    Finally. by OakField Photography, on Flickr

    Regards
    Patrick:D
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