Only if you take a new photo with different framing. That is, if you move closer to the subject (as you would if you want the same picture) your DOF will stay the same if your subject is the same size in the view finder.
Actually, you were extremely close. A 300f/2.8 lens on a 35mm camera has about the same DOF as a 400f/2.8 lens on a D60, and that's what I used. I was just demonstrating that while the longer telephoto lenses don't have less DOF, they do have a nice blur effect due to the perspective distortion. That being said, I could have taken the same shot with a 28mm lens (and gotten closer) and the duck just behind the first one would have looked about the same.
Nope, no photoshop. Actually, I moved back from the Duck just to get the whole duck in focus, because when I was closer I couldn't get the DOF across it's body.I hate to say it looks photoshopped but the foreground focus looks
a bit unatural for a Gx camera and mighty shallow. If you are
getting this out of camera I would really like to know how!
Sorry to repeat myself, but you will not get shallower DOF with a 2x adapter lens. You will get slightly blurrier backgrounds. I used to use the telephoto adapters to do this on the G2, but it's so tough I've given up. I've sold my Tiffen 2x, and am going to sell my Canon 1.5x. Here's a shot I happen to have from the G2+1.5x:
It's important to note that focal length is a squared term, and so is subject distance.... so they cancel. So, you can actually reduce your list to two things..
so, if you're not a newbie, then leave this thread - it'll just
make you laugh
otherwise, if you're like me (very new to photography), then read on!
I've had my G2 for a few weeks now, and have only now worked out
how to take a proper shot using short Depth of Field - you know,
the blurry effect you can have on backgrounds.
Heres how I did it with my G2:
isn't photography great!!! trying doing that on a Point and Shoot!!
- goto AV mode
- zoom the lens all the way out
- change the apature to 2.5 (or as low as it will go)
- take pic of subject relatively close up.
- vioila! blurry background!!!!
Yes, at full tele, the G3 will only allow f/3.0.
I've done a little research because I was taught many times and read everywhere that DOF was dependent on aperture, subject distance and focal lenght and what you wrote went the opposite direction. Check http://www.dpreview.com/learn/Glossary/Photographic/Depth_of_field_01.htm .
--For portrait it won't work that well, the camera will be unable to
focus at anything over 50 cms or so. I guess it might work for
extreme closeups
No, nothing I said went in the opposite direction of any good info. What I said was that the DOF is inversely proportional to the square of focal lenght, and inversely proportion to the square of subject distance. Because of this focal length cancels subject distance almost perfectly, and you get the same DOF.
You used the calculator wrong. Now you've got two entirely different pictures because you've changed the subject magnification. Let's fill in the calculator with the correct information:
There have been many pages put up to dis-prove this myth. Do a search, or tell me if you can't find them.
Of course it doesn't effect DOF, but it increases blur of the background. This is not short DOF, but has similar appearance.
As I've shown from your calculator, the figures do not show it. We aren't talking about the same thing, because you specifically mentioned "backing off" and "use full tele."
I think it's worth pointing out that I used to think this too. It just made sense I thought. Over the years, with the help of some very intelligent people on the topic of DOF (Karlg for instance) I've finally learned the difference aspects of DOF. Actual examples of this in action help too, as do calculators that show this effect.
Whoops, I guess I got carried away with "inversely." Obviously they wouldn't cancel (instead sum) if they were both inverse relationships. DOF is proportional to the square of subject distance.
Yep.
Yes, I put them together because they have the same effect. That way, it gives the photographer options.
Yes, you've got it up to this point. Increase your subject magnification, and you decrease your DOF.
What cancels is DOF when you don't change subject magnifcation. So, if you zoom in and don't change subject magnification (by moving back as was mentioned earlier) the DOF will stay the same. Also, if you move closer and zoom out appropriately, the DOF will stay the same (terms cancel.)
I understand why you say my figures produce different pictures because of the subject magnification relative to the frame. What I don't get is why you use 1.5ft and not 6ft.
I'm going to visit these newbie only threads more often Egg they are just swarming with experts! I think I learned more about DOF here than in the more so callsofisticated teaching sites. Thanks for all the info guys.so, if you're not a newbie, then leave this thread - it'll just
make you laugh
--Zack, Very interesting discussion and I love that calculator. I wish Canon would incorporate a DOF scale into the manual focus option. As to the 420 changing DOF, I have been using it to allow me to increase my f-stop (reduce aperture) which increases DOF so, In effect, the 420 does affect DOF, albeit in a backdoor sort of way. Right?Use of flash will not affect DOF. Bouncing it will illuminate the
background further and possible making the background more
noticable, but it will not change any focus quality in regards to
DOF.
Have fun! Glad you are getting that 420ex. Wish I got a
commission check with it!
Cheers,
Zack Arias
Atlanta, GA
http://www.usedfilm.com
Macro people tend to think in terms of subject magnification a lot, but the more natural instinct is to do it in terms of subject distance etc.. I think though, that people are even better at determining the field of view of an image over determining distance. That's why I am a fan of it. So, if you know your group shot is about 10 feet wide, you know from that chart exactly what aperture you need to get say 2 feet of DOF.
You know... I have no farging idea. I was taught the three items. It's like electricity. I don't know how it works but I use it everyday.
As far as using wide angle and getting close to eliminate camera shake.... this is fine UNLESS you want to compress the subject to background distance, in which case telephoto must be used.
Correct, as long as we're talking about rather big magnifications, or, IOW,
The formula blows up at extremely large magnifications, not small ones.
