Will a more expensive lens on my Canon 20D improve this pic?
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From: J. Clarke on 17 Jan 2010 14:09 Charles Packer wrote: > On Jan 17, 4:19 am, Robert Spanjaard <spamt...(a)arumes.com> wrote: >> On Sat, 16 Jan 2010 05:04:40 -0800, Charles Packer wrote: >>> For the three scenes I'm shooting with a tripod at a fixed location >>> [...] I can use all the speed I can get for the low light >>> conditions I'm shooting in. >> >> Why do you need all the speed you can get, if you're using a tripod? > > I shoot before dawn on clear days (to be free of shadow), a > little later on cloudy days. My shutter speed is typically > around 1/15 second, but on many days I need to go down as > to 1/8 or 1/6. On cloudy days when I can shoot at 9 AM I > can use 1/30. At these speeds I have to accept any blur > caused by wind moving the tree branches, but a plus of > shooting early in the morning is that the air is usually still. > I'm using an ISO setting of 400. I would worry about > noise with ISO any higher. This is not normal photography! > I intentionally "blow" the sky because I'm going to crop > it out anyway. The trees are way dimmer than the sky and > I try to get the tree part of the histogram as high on the > x-axis as possible. > > My scenes fall within the zoom range of 25-50mm, so I > need a lens that includes that range. An e-mail response > said I should just buy a Canon Tli because its kit lens > is much improved. Dunno if I want to deal with 15 > megapixels instead of the 8+ I have now, though... This is a wonderful post--you know _exactly_ what you want to do and state specifically what the shortcomings of your existing equipment are for that purpose. It's rare to see that. It seems to me that what you would in an ideal world like to be able to do is shoot at about 1/focal length (the "rule of thumb" for hand-holding non-IS lenses--in the absence of more information on subject motion it seems a reasonable place to start) in your worst-case conditions. So let's assume that you're at the 25mm end of your stated range. So you want to shoot at 1/25 and you're now shooting at 1/6. That's close enough to 2 stops to make no never mind. So how fast a lens would you need? 2 stops faster than f/3.5 is f/1.8. In an EOS-mount zoom that's not available. You can come pretty close in a prime--the Canon 28mm f/1.8 for example. In a zoom that fits Canon the best you're going to do is f/2.8, which puts you 2/3 stop faster than f/3.5 and you need to make up another 1-1/3 stop somewhere--the only way you can do that is to bump the ISO to around 1000, which you have stated will give an unacceptable noise level in your existing body. Alternatively you could live with a marginally improved shutter speed of 1/10 sec or so. Let's look at the other end of the zoom range now. At 50mm you would be wanting to shoot at 1/50. That's 3 stops faster you need to be. At 50mm your lens is giving you an aperture of 5.6, so 3 stops faster would be f/2.0. You can do that with an f/2.0 prime easily, but if you're using a zoom you're at f/2.8 and need to make up another stop somewhere. But you've gained two stops that puts your shutter speed at 1/24. To get to 1/50 you need to increase your ISO to 800. So, you can get the desired shutter speeds with prime lenses, but that pretty much restricts you to three points in your focal range--you can get primes that are 24mm, 35mm, and 50mm or within a few mm of each of those points easily, but in between they are rarer. Alternatively you could try to find a camera that gives acceptable results at ISO 1000. Since the review sites have changed their reporting methods since the 20d was tested, it's hard to find a direct comparison, but what I'm seeing is that Nikon d5000 seems to have about the same noise levels at ISO 800 or so that the T1i has at 400, so that with an f/2.8 zoom could potentially give you acceptable results at the desired shutter speeds. There are several f/2.8 zooms for the d5000 that cover the range you need--Tamron has one for a reasonable price that has excellent sharpness--its chromatic aberration is not so good, but still should be better than what you're using and you may be able to correct that acceptably in post-processing. Another alternative is to find a camera for which there is an f/2.0 zoom available in the range you need. Turns out that there is. In the dpreview tests the Olympus e-620 shows noise performance at ISO 400 in the same ballpark at the T1i, and there is a 14-35 f/2.0 lens for it (the Olympus uses a smaller sensor than the Nikon and Canon, so that lens on an Olympus body gives the same field of view more or less as a 28-70 on a Nikon or Canon). Downside is that it's an expensive lens--1800 bucks or so from B&H--so you're out the door at 2500 or so for lens and camera. Another consideration is that if 8 megapixels is OK for your use then you can apply some pretty heavy noise reduction to the images from any of the newer high pixel count cameras and and still have detail at the same level as your 20d, which means that you would be able to shoot at higher ISOs--exactly how high you'd be able to go I have no idea. So you've got several options, on paper anyway. If you can rent or borrow the Nikon and Olympus with the kit lenses you might want to do a side by side with your existing kit in the field and make sure that the noise levels on paper translate to your particular stretch of the real world. Once you have that information you should be able to make a more informed decision about which way to go.
From: Ray Fischer on 17 Jan 2010 15:40 J. Clarke <jclarke.usenet(a)cox.net> wrote: >Charles Packer wrote: >> My scenes fall within the zoom range of 25-50mm, so I >> need a lens that includes that range. An e-mail response >> said I should just buy a Canon Tli because its kit lens >> is much improved. Dunno if I want to deal with 15 >> megapixels instead of the 8+ I have now, though... > >This is a wonderful post--you know _exactly_ what you want to do and state >specifically what the shortcomings of your existing equipment are for that >purpose. It's rare to see that. While I agree that he is unusually clear in his requirements, there is one requirement that is missing: Is he looking for a cheap solution or an excuse to buy better gear? :-) -- Ray Fischer rfischer(a)sonic.net
From: Charles Packer on 18 Jan 2010 09:23 On Jan 17, 2:09 pm, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > So you've got several options, on paper anyway. If you can rent or borrow > the Nikon and Olympus with the kit lenses you might want to do a side by > side with your existing kit in the field and make sure that the noise levels > on paper translate to your particular stretch of the real world. Once you > have that information you should be able to make a more informed decision > about which way to go. Thanks for laying out all the options like that. Basically, for all the work I'm putting into this project, I want to make sure I'm not overlooking any obvious improvement in equipment that I could be making. Since my three scenes are at very close to the 24, 35 and 50 mm of available fixed lenses, I should at least give one a try. I see that for $100, B&H has the EF 50mm f1.8. Also, the idea of renting a high-end combination for comparison purposes is attractive. -- Charles Packer http://cpacker.org/whatnews mailboxATcpacker.org
From: Better Info on 18 Jan 2010 11:21 On Sun, 17 Jan 2010 05:31:12 -0800 (PST), Charles Packer <mailbox(a)cpacker.org> wrote: >On Jan 17, 4:19 am, Robert Spanjaard <spamt...(a)arumes.com> wrote: >> On Sat, 16 Jan 2010 05:04:40 -0800, Charles Packer wrote: >> > For the three scenes I'm shooting with a tripod at a fixed location >> [...] >> > I can use all the speed I can get for the low light conditions I'm >> > shooting in. >> >> Why do you need all the speed you can get, if you're using a tripod? > >I shoot before dawn on clear days (to be free of shadow), a >little later on cloudy days. My shutter speed is typically >around 1/15 second, but on many days I need to go down as >to 1/8 or 1/6. On cloudy days when I can shoot at 9 AM I >can use 1/30. At these speeds I have to accept any blur >caused by wind moving the tree branches, but a plus of >shooting early in the morning is that the air is usually still. >I'm using an ISO setting of 400. I would worry about >noise with ISO any higher. This is not normal photography! >I intentionally "blow" the sky because I'm going to crop >it out anyway. The trees are way dimmer than the sky and >I try to get the tree part of the histogram as high on the >x-axis as possible. > >My scenes fall within the zoom range of 25-50mm, so I >need a lens that includes that range. An e-mail response >said I should just buy a Canon Tli because its kit lens >is much improved. Dunno if I want to deal with 15 >megapixels instead of the 8+ I have now, though... And yet, doing time-lapse over months or years of time requires a 100% reproducible zoom position to duplicate each frame with the exact same FOV as the last, as well as the exact same focus setting. Check into the uBASIC script commands of "set_zoom" and "set_focus". Both can lock a camera's lens into the exact same setting each and every time. For stop-frame animators and time-lapse photographers there's no better system on earth. <http://chdk.wikia.com/wiki/UBASIC/TutorialScratchpad#The_set_zoom.2C_set_zoom_rel.2C_get_zoom.2C_set_zoom_speed_commands> <http://chdk.wikia.com/wiki/UBASIC/TutorialScratchpad#The_set_focus_and_get_focus_commands> (They're not too bright, are they? Of course not! That's why they always choose the perfectly wrong cameras for the perfectly wrong reasons and perfectly wrong purposes. I always like to keep in mind, "Never underestimate the stupidity of humanity." Then I'm never disappointed.)
From: J. Clarke on 18 Jan 2010 13:25
Charles Packer wrote: > On Jan 17, 2:09 pm, "J. Clarke" <jclarke.use...(a)cox.net> wrote: >> So you've got several options, on paper anyway. If you can rent or >> borrow the Nikon and Olympus with the kit lenses you might want to >> do a side by side with your existing kit in the field and make sure >> that the noise levels on paper translate to your particular stretch >> of the real world. Once you have that information you should be >> able to make a more informed decision about which way to go. > > Thanks for laying out all the options like that. > Basically, for all the work I'm putting into this > project, I want to make sure I'm not overlooking > any obvious improvement in equipment that I could > be making. Since my three scenes are at very close > to the 24, 35 and 50 mm of available fixed lenses, > I should at least give one a try. I see that for $100, > B&H has the EF 50mm f1.8. Also, the idea of renting > a high-end combination for comparison purposes is > attractive. Glad to be of help. |