The big questions about DSLRs
in [Digital Cameras]
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From: Chris Malcolm on 23 Apr 2010 18:37 In rec.photo.digital Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote: > Chris Malcolm wrote: >> In rec.photo.digital Pete <available.on.request(a)aserver.invalid> wrote: >>> On 2010-04-22 18:48:08 +0100, C J Campbell said: >>>> On 2010-04-22 01:00:32 -0700, "Ray Shafranski" <me(a)privacy.net> said: >>>>> The lifting mirror and the pentaprism/pentamirror are relics of film days >>>>> and should be replaced on all DSLR designs. >>>> Not so much a relic of film but of the need for clear, bright, optical >>>> viewfinders. You are not going to get as good a picture holding the >>>> camera out in front of you (as you must do with the Olympus E-PL1, for >>>> example) as you will with the camera braced by your face. Mirrorless is >>>> great for the photography masses who really don't care about picture >>>> quality, but it has a ways to go before it is usable by pros. So, I >>>> would say the lifting mirror and pentaprism will disappear on consumer >>>> DSLRs soon, but it is going to be on pro cameras for awhile yet. >> >>> Yes, and until sensors plus software can exceed the night-adaptive >>> vision of the human eye, framing of very low light shots will remain a >>> difficulty without an optical finder. >> >> That point has been reached. In the very dimmest conditions I have to >> use the LCD of my DSLR because I can see more than I can through the >> optical viewfinder or with the naked eye. This was demonstrated very >> clearly recently when I tried to take available light shots in a dark >> tunnel. At ISO 200 and f8 the shutter speed required was more than 30 >> minutes. > Something wrong with your numbers there. If it was that dark then the 1s > time averaged viewfinder image would still be 11 stops underexposed > which would be indistinguishable from black cat in a coal cellar. The exposure was 30+ mins at f8. And with the lens stopped down to f8 ay ISO 200 I could see nothing. Nor was the camera capable of metering an exposure. I used a light meter. > Dazzle > from the LCD can be a nuisance in low light conditions too. Unless the LCD brightness auto adjusts itself relative to the ambient light level. That's a very handy feature. > Which SLR can meter for a 30 min exposure at 200 ASA? Yet another good reason to carry a light meter :-) > I'd be surprised > if on that timescale the image wasn't dominated by stray IR photons in > the sensor and warm spots from the control electronics. If the camera was set to f8 and ISO 200 nothing could be seen. But if I whacked the ISO to maximum and set the aperture to f1.4 there was a visible image. I saw no warm spots. There was a lot of stray noise swimming about in the LCD like a weak TV signal, but it was seeing more detail than my dark adapted eyes could see. But I wasn't prepared to hang around for 30 minutes to take the shot. I only had the pop up flash which was useless because it fell off too fast in a long narrow tunnel. So I ended up light painting the shot rather unevenly with a torch. > Astronomical cameras can now focus better than humans by repeatedly > sampling highlights in the image, but generic DSLR autofocus tends to > hunt in low light conditions and manual focus is more reliable. I used the torch to get a reliable autofocus. -- Chris Malcolm
From: Chris Malcolm on 23 Apr 2010 19:22 In rec.photo.digital Chris Malcolm <cam(a)holyrood.ed.ac.uk> wrote: > In rec.photo.digital Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote: >> Chris Malcolm wrote: >>> In rec.photo.digital Pete <available.on.request(a)aserver.invalid> wrote: >>>> On 2010-04-22 18:48:08 +0100, C J Campbell said: >>>>> On 2010-04-22 01:00:32 -0700, "Ray Shafranski" <me(a)privacy.net> said: >>>>>> The lifting mirror and the pentaprism/pentamirror are relics of film days >>>>>> and should be replaced on all DSLR designs. >>>>> Not so much a relic of film but of the need for clear, bright, optical >>>>> viewfinders. You are not going to get as good a picture holding the >>>>> camera out in front of you (as you must do with the Olympus E-PL1, for >>>>> example) as you will with the camera braced by your face. Mirrorless is >>>>> great for the photography masses who really don't care about picture >>>>> quality, but it has a ways to go before it is usable by pros. So, I >>>>> would say the lifting mirror and pentaprism will disappear on consumer >>>>> DSLRs soon, but it is going to be on pro cameras for awhile yet. >>> >>>> Yes, and until sensors plus software can exceed the night-adaptive >>>> vision of the human eye, framing of very low light shots will remain a >>>> difficulty without an optical finder. >>> >>> That point has been reached. In the very dimmest conditions I have to >>> use the LCD of my DSLR because I can see more than I can through the >>> optical viewfinder or with the naked eye. This was demonstrated very >>> clearly recently when I tried to take available light shots in a dark >>> tunnel. At ISO 200 and f8 the shutter speed required was more than 30 >>> minutes. >> Something wrong with your numbers there. If it was that dark then the 1s >> time averaged viewfinder image would still be 11 stops underexposed >> which would be indistinguishable from black cat in a coal cellar. > The exposure was 30+ mins at f8. And with the lens stopped down to f8 > ay ISO 200 I could see nothing. Nor was the camera capable of metering > an exposure. I used a light meter. How embarrassing! I remembered correctly that the camera couldn't meter it. But the doddering old fool in charge of my memory dropped the memories as he tottered back from the archives and instead made up some plausible fiction about the light meter. After seeing the query in this thread about what light meter could meter such dim light I thought I ought to check. Mine doesn't! So I went back and looked at my written notes of the time. In fact how I measured the exposure was the simple old fashioned method. I opened the lens to f1.4, whacked the ISO to max, and found the right exposure by experiment. Then I simply adjusted the time for f8 and ISO 200. -- Chris Malcolm
From: Chris Malcolm on 23 Apr 2010 19:43 In rec.photo.digital DanP <dan.petre(a)gmail.com> wrote: > On 23 Apr, 01:11, Chris Malcolm <c...(a)holyrood.ed.ac.uk> wrote: >> That point has been reached. In the very dimmest conditions I have to >> use the LCD of my DSLR because I can see more than I can through the >> optical viewfinder or with the naked eye. This was demonstrated very >> clearly recently when I tried to take available light shots in a dark >> tunnel. At ISO 200 and f8 the shutter speed required was more than 30 >> minutes. >> >> -- >> Chris Malcolm- Hide quoted text - > But I bet you have taken a shot, loked at it on the LCD and decided > what to do next. > I do not know of any camera with Live View that can give a better view > that the optical viewfinder. > The point is optical viewfinder beats LIve View at the moment. > If I am wrong please tell me the make of your camera. You're both right and wrong. It's a Sony A550 which has two different live views from two different sensors. One can't do it but the other can. The normal live view from the special dedicated live view sensor isn't as good in dim light as the optical viewfinder or naked eye. But the manual focus live view check uses the image sensor, and that gives a much brighter image in dim light than the optical viewfinder or indeed the naked eye. You can easily read printed text with it when the light is too dim to read it with the naked eye. And zoom right up to pixel level if you want. It's so amazingly good it has to be seen to be believed! -- Chris Malcolm
From: Wilba on 23 Apr 2010 21:13 DanP wrote: > I do not know of any camera with Live View that can give a better > view that the optical viewfinder. Try any current Live View camera with exposure simulation on a macro shot with a reversed lens set to the exposure aperture (e.g. f/16). The image in the viewfinder will be like -5 EV, while the Live View image will look like a well-exposed shot. Compare the macro focussing accuracy you get through the viewfinder with what you can get zoomed in five or ten times in Live View. > The point is optical viewfinder beats LIve View at the moment. For normal shots (autofocus in good light), yes. For macro there are huge advantages to Live View that mean you can do things that are impossible optically, e.g. view the live image on a computer monitor and remotely control the camera.
From: LOL! on 23 Apr 2010 21:54
On Fri, 23 Apr 2010 15:41:33 -0500, George Kerby <ghost_topper(a)hotmail.com> wrote: > > > >On 4/23/10 11:56 AM, in article jnj3t5hhnp5k6857uml4gga8h3ki5j72s0(a)4ax.com, >"Phil B." <pblackwell(a)spamlessyahoo.com> wrote: > >> On Fri, 23 Apr 2010 11:36:19 +0100, "11:11" <1112(a)1113.com> wrote: >> >>> "RichA" <rander3127(a)gmail.com> wrote in message >>> news:1fd97cd6-3a04-4e15-ad54-670b393393aa(a)q31g2000prf.googlegroups.com... >>>> Canon. Will they release a compact non-mirrored, interchangeable lens >>>> camera? >>>> Nikon. Will they release a compact non-mirrored camera and/or an , >>>> high megapixel FF camera that doesn't cost $8000? >>>> Olympus. Will they dump DSLRs? >>>> Pentax. Will they release a FF camera, will they survive? >>>> Sony. Will they release a non-boring entry level camera? >>>> Fuji. Will they release a new pro DSLR or any interchangeable lens >>>> camera? >>>> Sigma. Does anyone care? >>>> Samsung. Will they make a dent in 4/3rds sales? >>> >>> >>> >>> I'm wondering when someone will bring out a large sensor p&s that takes >>> photos when you actually press the button and maybe even a decent burst >>> rate. >>> >> >> Do catch up with reality some day. Cameras like that have been out for many >> years now. Most P&S cameras today have shutter-lags far less than any DSLR >> made today. Shutter-lags on the order of 30-45ms. They don't have to waste >> time lifting that loud slapping mirror out of the way. All DSLR shutter-lag >> averages 60-130ms or more. Some P&S cameras even take continuous frames >> held in the buffer and will let you keep several shots that were taken >> before you even press the shutter. In order for you to get those images >> where in the past you saw something happening, lifted the camera, and said >> to yourself, "Damn, I just missed that shot". The camera has already been >> taking them for you, then lets you select which one it was that you thought >> you had missed and wanted. >> >> Are you DSLR fools really this ignorant? No, don't bother answering that. >> You prove it with every post that you make. Keep on living in last >> century's technology. Ignorance is bliss after-all, isn't it. >> >> >And another one! Thanks for quoting these. Some might miss these valuable FACTS the first time. LOL!!!!!!!!!! |