Two of four reaction wheels seized up, critical for precise photometry
Excerpt from the Kepler Mission Manager Update. (h/t to Dr. Leif Svalgaard)
At our semi-weekly contact on Tuesday, May 14, 2013, we found the Kepler spacecraft once again in safe mode. As was the case earlier this month, this was a Thruster-Controlled Safe Mode. The root cause is not yet known, however the proximate cause appears to be an attitude error….
…We attempted to return to reaction wheel control as the spacecraft rotated into communication…but reaction wheel 4 remained at full torque while the spin rate dropped to zero. This is a clear indication that there has been an internal failure within the reaction wheel, likely a structural failure of the wheel bearing. The spacecraft was then transitioned back to Thruster-Controlled Safe Mode.
An Anomaly Review Board concurred that the data appear to unambiguously indicate a wheel 4 failure, and that the team’s priority is to complete preparations to enter Point Rest State. Point Rest State is a loosely-pointed, thruster-controlled state that minimizes fuels usage while providing a continuous X-band communication downlink. The software to execute that state was loaded to the spacecraft last week, and last night the team completed the upload of the parameters the software will use.
The spacecraft is stable and safe, if still burning fuel…In its current mode, our fuel will last for several months. Point Rest State would extend that period to years.
…We will take the next several days and weeks to assess our options and develop new command products. These options are likely to include steps to attempt to recover wheel functionality and to investigate the utility of a hybrid mode, using both wheels and thrusters.
With the failure of a second reaction wheel, it’s unlikely that the spacecraft will be able to return to the high pointing accuracy that enables its high-precision photometry. However, no decision has been made to end data collection.
Kepler had successfully completed its primary three-and-a-half year mission and entered an extended mission phase in November 2012.
Even if data collection were to end, the mission has substantial quantities of data on the ground yet to be fully analyzed, and the string of scientific discoveries is expected to continue for years to come….
Read the full Mission Manager Update.
In a New York Times article, astronaut John Grunsfeld, now in charge of NASA Science Mission Directorate under which Kepler operates, is quoted: “For Mr. Grunsfeld, who played mechanic to the Hubble telescope during several lengthy spacewalks, the Kepler malfunction looked particularly frustrating. ‘Unfortunately, it’s not in a place where I can go and fix it,’ he said.”
What does reaction wheel 4 look like?
(see photo at right)
Where are the reaction wheels on the spacecraft?
too hilarious not to get into the WUWT comments ASAP, even if it’s O/T:
18 May: Sydney Morning Herald: Peter Hannam: Obama gives Aussie researcher 31,541,507 reasons to celebrate
It’s the social media equivalent of hitting the jackpot: having your study tweeted by US President Barack Obama.
Australian researcher John Cook, an expert in climate change communication, was inundated with requests for interviews by US media outlets after Obama took to Twitter to endorse his project’s final report…
Bullying
While most of the interest has been positive, Mr Cook expects some negative attention from those who reject the scientific consensus – something that some academics have found to their dismay.
“Generally the level of hate you get is in proportion to the impact you have,” he said.
“There’s an increase in academic bullying where climate deniers are sending complaints to journals or the university … and this actually works.
“I’ve have anecdotal examples of academics who are scared of that kind of reaction and who are playing things close to their chest – which is a real shame,” he said.
http://www.smh.com.au/environment/climate-change/obama-gives-aussie-researcher-31541507-reasons-to-celebrate-20130517-2jqrh.html
One is reminded of that old saying (I think originally by Robert Heinlein): “Nothing that contains moving parts is ever satisfactory from an engineering viewpoint”
date for Sydney Morning Herald tweet article should be 17 May.
can’t resist adding this:
24 Aug 2012: USA Today: David Jackson: Obama has millions of fake Twitter followers
President Obama’s Twitter account has 18.8 million followers — but more than half of them really don’t exist, according to reports.
A new Web tool has determined that 70% of Obama’s crowd includes “fake followers,” The New York Times reports in a story about how Twitter followers can be purchased.
“The practice has become so widespread that StatusPeople, a social media management company in London, released a Web tool last month called the Fake Follower Check that it says can ascertain how many fake followers you and your friends have,” the Times reports…
http://content.usatoday.com/communities/theoval/post/2012/08/obama-has-millions-of-fake-twitter-followers/1
Nothing lasts forever, at least, not at current levels of technology… and some things have never worked anywhere near as well in space, as they do in a gravity well.
Still as they say, there are years of analysis yet to be done on what Kepler has picked up. Looking forward to seeing it!
Ironic that probably one of the oldest toys known to man, the spinning top, should be the cause of a failure in one of the most sophisticated instruments built by mankind.
“the proximate cause appears to be an attitude error….”
It’s bound to have an attitude problem, it’s a youngster!
Well, I never! Watched a program on BBC TV Channel 5 last titled “Aliens: Are we Alone?”. It was about the Kepler spacecraft and all the planets it had discovered. Impressive science. Photo-shopped aliens we rather junior grade. Sad it’s bust.
Perhaps in the years it can stay in safe mode, a civilian ‘space shuttle’ can go and repair it. It would be cheaper than building yet another orbiting telescope.
This one, again, seems like a misallocation of public funds. Other than the gee-whiz announcements wouldn’t public funds be better spent on things like the Sun, the Moon and all those rocks and comets zooming around a bit closer to home?
I’m all for gathering knowledge just for the sake of knowing but shouldn’t private donations fund projects like these?
I used to build little mechanical devices that had to operate in UHV (ultra high vacuum) as part of my graduate research. You immediately appreciate how engineering becomes a lot more complicated once you have no air. Lubricants vaporize, temperature control is tough; you lose convective and most of conductive heat transfer, and metal likes to “gall” especially stainless steel. I’m amazed the vast amount of stuff sent into space that works as well and as long as it does. From my experience I don’t think ” why did this fail” but “why did it ever work”?
@Ian, nope. It’s orbiting the sun in a slightly longer period orbit than the earth and is already something like half an AU behind us. By the time we have the technology to travel out, repair it and return it’ll probably be on the far side of the sun and cooked like a rotisserie chicken.
David L says “Lubricants vaporize”. But of course that is what they do in a vacuum – and that is why you should not use a lubricant. There are such things as magnets. Where you have an important control function that depends on movement, such as these reaction wheels, you use magnetic bearings. Magnetize the axle, N pole at one end and S pole the other. Then put three small magnets around the N pole end, 120 degrees apart, with their N end to the axle and one more longitudinally with the axle, similar at the S end. Then all magnets repel the axle and since the wheel is not affected by gravity the axle and the wheel “float” in space unaffected by friction. I say “Not affected by gravity” on the grounds that the force of gravity on it is exactly balanced by the outward acceleration due to the orbit.
@Dudley Horscroft on May 17, 2013 at 2:43 am
Very true. My point is one needs complicated engineering solutions to rather simple operations here on the surface such as you described to get around the inability to use simple ball bearings and lubricants. Which, by the way, we used pure Molybdenum Disulphide (the active imgredient in Never-Seez) as a dry lubricant for a lot of applications.
“…the mission has substantial quantities of data on the ground yet to be fully analyzed, and the string of scientific discoveries is expected to continue for years to come….”
…which should be released in full instead of greedily hoarded. FOIA, anyone? 😉
…We attempted to return to reaction wheel control as the spacecraft rotated into communication…but reaction wheel 4 remained at full torque while the spin rate dropped to zero….
I’ve got a bike in my garage like that…..
Off topic:
Are we having a sea ice minimum poll this year?
Would be nice to beat the “experts” over at Neven’s.
And humorous comments aside, this is sad. Of all the ways to fail… sigh.
On the other hand, it did accomplish its primary mission.
Erik Anderson says:
May 17, 2013 at 3:10 am
“…the mission has substantial quantities of data on the ground yet to be fully analyzed, and the string of scientific discoveries is expected to continue for years to come….”
…which should be released in full instead of greedily hoarded. FOIA, anyone? 😉
=================================
Why don’t you ask them for a copy the data? I suspect, don’t know for sure, that it won’t take you long to discover that the problem isn’t that you can’t have the data, but that you won’t be able to make much sense out of it without many years of work and R&D on your part?
But first check http://keplergo.arc.nasa.gov/ArchiveSchedule.shtml and see what is already available to the public
….”the mission has substantial quantities of data on the ground yet to be analyzed”….
Translation: NASA has some ‘data adjustment’ and photo-shopping yet to do….
can’t have the raw space alien flyby photos on the super market tabloid covers….
with those silly “Take Us to Your Leader” bumper stickers showing….
because….obviously….we are now leaderless….what, me worry ?
Unfortunate — Kepler was making a huge number of discoveries. Seems like reaction wheels/gyroscopes are a weak-link for many satellites.
Here’s more on some possible actions:
http://www.universetoday.com/102188/more-insight-on-how-nasa-might-revive-the-kepler-space-telescope/
Re Neil’s comment “David L. masterfully handled Dudley Horscroft’s attempted affront. Even the heights of scientific snobbery are no match for true humility. Well done David.” I’ve carefully checked my comments and David’s and see no ‘affront’ to anyone. I have no problem with David L’s response, either. If anyone was affronted, then I apologize!
Bigger problem is dwisehart’s comment: “@Dudley Horscroft the problem is that these are reaction wheels, which means you want to develop a torque through the bearings–magnetic or otherwise–that will right the spacecraft. So magnetic bearings will work only if they develop a fair bit of torque between the spinning wheel and its mount. That would make any magnetic system large and heavy, two bad qualities for spacecraft.”
Perhaps the problem is my understanding of a “reaction wheel”. If you have a spinning wheel, as per gyroscope, to keep a body correctly aligned in space, if there is friction at the axle bearings the body will start rotating and gradually accelerate as the wheel slows till they are both rotating at the same rate. So you must have no friction at the bearings. What you must be able to do is put a force on the wheel to turn it one way, and the reaction (Newton!) will turn the body the amount you want in the other way. When correctly aligned, remove force. So the force should be applied to the circumference of the wheel – standard three phase AC stuff where rotor and stator are not in contact and hence no friction.
Rob L comments:”Magnetic bearings are not a particularly great solution – they require active electromagnetic control systems to maintain stable operation if operating through zero speed (checkout Earnshaw’s theorum for explanation), or superconducting elements that are just not feasible on a spacecraft. They also need mechanical bearing backups for when/if power or control fails.” The whole point is that a magnetic bearing as I described needs no control system whatsoever. The axle is held away from all contact with other materials by magnetic repulsion. The inverse Square law means that the axle cannot contact the bearings. As it is not spinning except when actually being used to rotate the craft, there are no gyroscopic forces which may overcome the repulsion of the magnets. No back up bearings are needed as there is no power or control system to fail. The only conceivable failure mode is for a permanent magnet to become demagnetized. Far more unlikely than a lubricant failure. See for example one of those toys, where a magnetic ring hovers above a base staying permanently at the same height and the same distance from the rod through the ring. No power employed, no control system. Thinks: you could probably use two of them, glue bits of copper wire between them, and use a few hidden coils around the room to start and stop the rings rotating “as if by magic”! Introduction to elementary electricity and magnetism for High School students.
Attitude error huh? Just like my teenager….
Just about every satellite I have seen fail either lost its gyroscopes or ran out of fuel. Without attitude control, they are just so much space junk. At least this one won’t be a hazard to navigation, and it did give us a bonus year beyond design specs.
Its kind of quaint that some folk here seem to think We’ll ever have another space shuttle or such technology as to be able to repair something in a solar orbit.
@ tty
Your quote reminds me strongly of lines to similar effect in Arthur C. Clarke’s novel ‘The City and the Stars’.
Even if that’s not the source that you’re looking for, the book is worth reading for its own sake.
It’s a shame that Cook didn’t think to give a citation to his ‘bullying’ claims. If he had, we could then deplore it, the way we deplore the attempts to bankrupt Anthony’s business, or to ‘re-examine’ a Doctorate award, or to ‘redefine what peer reviewed literature is’, or to call for death camps for climate sceptics. All those bullying instances cited in WUWT. But without such a citation, it’s perfectly reasonable to conclude that just like the ‘death threats that weren’t’, this is a case of DARVO- Denial, Anger, and Reversing Victim and Offender.
@Dudley Horscroft the problem is that these are reaction wheels, which means you want to develop a torque through the bearings–magnetic or otherwise–that will right the spacecraft. So magnetic bearings will work only if they develop a fair bit of torque between the spinning wheel and its mount. That would make any magnetic system large and heavy, two bad qualities for spacecraft.
Great article. And that answers a previous question in the thread. This gyro is lubricated, not magnetically suspended.
TomB says:
Magnetic suspension on reaction wheels? Sounds sketchy. The point of reaction wheels is attitude control. If you magnetically suspend them you’re degrading the performance of your control because the physical coupling is now imprecise. This sounds like something I would avoid like the plague on a telescope satellite, but RCS’ are something I’ve never looked at for a failure analysis.
> “This is a clear indication that there has been an internal failure within the reaction wheel, likely a structural failure of the wheel bearing.”
These reactions-wheels are clearly not using magnetic-hubs … likely due to the fact that their purpose is not *just* to turn something but to impart steering-forces upon the entire space-craft
IMHO, these things are THE single-point-of-failure most likely to render a spacecraft useless and I wish they were more redundant than the have-4-need-3 paradigm … they are not a vast expense nor a large weight, and their function is mission-critical … it would be far better for cost-effective-long-term-survival to go with have 9-need-3 etc
It is really disappointing how often reaction wheels fail – in this case two out of four within 4 years. After 40-50 years in development you would think we could do better. Hubble had trouble with them too, as did Hayabusa and mars global surveyor amongst others. Given ongoing failures like this, there will probably be a bit more effort put into their development – they should be a simple, cheap, off the shelf, and multiply redundant item for space astronomical applications.
Magnetic bearings are not a particularly great solution – they require active electromagnetic control systems to maintain stable operation if operating through zero speed (checkout Earnshaw’s theorum for explanation), or superconducting elements that are just not feasible on a spacecraft. They also need mechanical bearing backups for when/if power or control fails.
I’m shocked that this telescope has only one spare reaction wheel. A mission critical moving part.
Not quite fair to bitch about it failing after it had already exceeded its design life. That’s like moping about a car going “just” 300k miles instead of 200k. The unexpected durability of the first Mars rovers has probably spoiled us.
Would it be possible to repair it with a remote controlled robot, a set of versatile arms and hands some maneuvering boosters and a tool belt. It may be a good Idea to design future satellites with repair droids in mind, HA! r2d2.
I speak heretically, I’m ready for a reaction, but what I ask is “who gives a shit?”
Uh pat, that’s not really his account even * … you’re good at research, I need not add more …
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(OFA property)
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Kaboom says:
May 17, 2013 at 9:33 am
Not quite fair to bitch about it failing after it had already exceeded its design life. That’s like moping about a car going “just” 300k miles instead of 200k. The unexpected durability of the first Mars rovers has probably spoiled us.
Kaboom,
Actually the most common reason why the primary service expectation low in satellites is because of the attitude control… gyroscope and such. So, the general lament, ala
Rob L says:
May 17, 2013 at 8:44 am
is quite valid.
Still wondering why we cannot have lot more redundancy in the pieces that are most prone to break… eg. 9 or 12 reaction wheels, where just 3 will do???
@Mark Wood says:
Control wheels are indeed very heavy. The point of an RCS is rotational inertia that is capable of being pushed off against to change the attitude of the craft. This eliminates the need for traditional reaction control thrusters which use up fuel. In theory, a reaction control wheel if it lasts, can change the attitude of the craft so long as there is electrical power. Unfortunately, since the craft we put into space need to be small and light, those wheels need to spin at fairly high RPMs, this imparts significant wear on the bearings, even in the weightlessness of space. It virtually guarantees they won’t last forever. If you’ve seen the reaction control wheels on the ISS, you’ve seen that they’re HUGE, 2 of them are the size of one medium-sized satellite, and I think the ISS has 4 or more of them. They’ve also had to replace some of them.
There is a solution… Ion propulsion reaction control thrusters. They still use fuel, but at a VERY low rate. The problem with ion propulsion is it’s expensive, and the RF power you generate will generally cause significant communication problems with your satellite.
Hi, Wamron (“I’m ready for a reaction”), here’s one.
On the one hand, I see your point. A wonderful machine that has accomplished much of great value, long past the end of its projected useful life, is dying.
On the other hand, there is something in a lot of us humans (not all, not all, I read you, W.), that deeply mourns the loss of our faithful, hardworking, creations (even if we didn’t build them, as the Kepler engineers did). I remember the day we drove “Brownie,” an old, ugly, Chevy Apache (1961, I think), to the junk yard a few years ago and left him there. We kept his turn indicator light, “Brownie’s soul,” we called it. We still have it. I wept as we drove away. Why was that? Because we loved that old truck. Irrational, yes, but, true.
Thus, I care about the Kepler. I care because there are some fine engineers (and many other professionals) who will mourn the loss of their amazing machine. I care about them.
David L. masterfully handled Dudley Horscroft’s attempted affront. Even the heights of scientific snobbery are no match for true humility. Well done David.
Mmmmm, I’m not so sure. It’s been 25 years or so since I was in the chemical process industry, but even then we were using magnetically coupled process pumps to move fluids you just didn’t want leaking out. There was a limit to the amount of torque you could transfer, but that was before the widespread availability of rare earth magnets. I might be more concerned about the magnetic fields you would be creating, but I’m sure there are engineering fixes or SOP’s to deal with that.
@Janice Moore….well that was a vastly more thoughtful and engaging reaction than I expected. Totally blind-sided me. I was expecting things like “oh you are an ignorant pillock Wamron” like the amateur astronomer who slated me as some kind of wife-beating savage. But no, you caught me out with the love of machines. Touche.
You are welcome to view my home: you would find I have a much greater variety of, mostly old, some ancient, photographic appliances on display in glass cases than you’ll see in most camera shops. I have cameras well over a century old and also some of the most recent. The entire range of formats and sizes up to half-plate (bigger than that are too large for me). Whats more Ive used both pre-WW2 and post-war era cameras and have superb images out of them.
So, yes, I do love machines. But I prefer ones I can handle, or even viewi n a museum (which my home has been compared to) not hundreds of thousands of miles away. I never considered it that way.
OK so if you love Kepler you must utterly worship the Voyager spacecraft!
@Feller with a big name:
“Still wondering why we cannot have lot more redundancy in the pieces that are most prone to break… eg. 9 or 12 reaction wheels, where just 3 will do???”
PAYLOAD MASS!
Dear Wamron,
What a pleasure to make a connection with you across cyber space. I’m so glad that you understood what I was trying to say. I would love to see your home. Maybe someday I will (I and someone else, if you are a man! — to avoid even the appearance of impropriety). It sounds like a warmly peaceful place of fascinating “decor” and happy nostalgia. Your photographic devices collection sounds impressive to say the least. Do you have one where you light off that powder (I can’t remember what it was – phosphorous?) to make a flash? Can you make a Daguerretype (sp)? I, too, am an amateur photographer (very basic). I still haven’t found a digital camera (at least one that I could afford!) that can perform as well as my old 35mm SLR. Except for trivial use, I can barely stand to use a digital camera — the lighting and, even more, the action-stopping (aaaarrrrrgh!) are, for me, very frustrating. I don’t WANT the camera to do it for me!!
On the other hand, it sure is wonderful to play around with all the digital processing on the computer… . Would be nice to have both worlds in one camera. I need to start reading up (I’m about 10 years out of date on camera technology!).
Well, must cut this short, since it is totally off topic. I, too, much prefer purely mechanical machines (esp. motor vehicles) with only basic electrical support systems. I don’t know diddly about how to repair them, but my brothers do. Yeah, I know quite a few “gear heads” and “motor heads.” That is why I have such deep sympathy for those Kepler engineers. Engineers are born fixers. Sitting here on earth watching a problem they know how to fix but can’t must be excruciating.
Take care,
Janice
Janice, sadly I have long been forced into relying upon digital. The cost of using 120 roll film on the Mamiya 645 and Press 23 that I used to love is too vast at the rate I took to shooting (several hundred exposures per session of a couple of hours). Plus Ive never had adequate scans from transparencies. But if you look at newer cameras, particularly SLRs, you’ll find that annoying shutter lag of ten years ago has effectively much vanished.You can use allyour oldest lenses on most systems too! Now Im being pushed increasingly from still to video anyway. Thats how they make us buy gear!
I guess you could shoot Dageurrotypes on one or two of mine with plates (its the process I believe, not the camera) but I dont have a tray for flash powder.I do however have some very kranky early flash bulb gear.
When I was young we would snigger at old electronic gear that took time to “warm up” whereas the new kit started immediately. I find it hilarious and also significant that todays digital gear takes ages to “boot up”. Is it progress? The ergonomics of modern cameras is superb, but I find most other digital appliances are appalling in practice with an interface dependent upon having dainty fingers and perfect, youthful dexterity.
Thanks for all that great info., Wamron. Re: digital appliance interfaces generally — they STINK. Obviously there were no first-class engineers allowed in on the camera, phone, and other products’ designs!
Two steps forward, 1 back…
Galane, that would work except it’s a hardware error… maybe they could pull the RAM, blow on the contacts, and reseat it 😉
Janice, if you’re looking for a decent digital camera, try a Sony NEX5 (or 6 or 7). I bought one second hand for $250 and had no idea what it was, the original owner had his camera bag stolen and got the whole kit replaced on insurance so he sold me the camera and lens. I ordered new batteries and charger from China on ebay and had to wait weeks to see how good it was.
I was blown away. It’s a pro quality camera but it’s SMALL – since it doesn’t have a flip up mirror and prism like a traditional SLR (totally not needed for digital work, but essential for film) it uses a screen on the back for framing, like a cheapo.
At 14 megapixels the images are large, the quality of the images is amazing, with a perfect balance of color and contrast right off the card. I had been lamenting the loss of my beloved 35mm rig and didn’t want to spend thousands on something new, this was a perfect solution. When it breaks or is lost or whatever I’ll buy another like it. You can throw it into manual mode and adjust everything, or you can slap it into full auto and get good shots.
No learning curve, and I was able to use my Nikon 35mm lenses and accessories with a simple $12 adapter ring (also China, ebay). It’s ready to shoot immediately, saves images as quick as you can take them, and has none of the other issues I had with digital cameras. It even shoots HD video with better than “acceptable” quality.
(Re: the vehicle… I kept my last car for 23 years… it was my daily driver for 22. That last year I just left it in the driveway because I couldn’t bear to part with it… so many memories wrapped up in one piece of hardware)
Code Tech…..everyone swears by the camera they like.BUT..the Sony NEX series HAS NO FECKING VIEWFINDER!!!!!!!!!!!!!!
No, a viewfinder is essential for good camera stance. Sorry, you need an SLR or if you want no mirror, an SLT.
Code Tech…re your car, Im the same with an old pair of shios. Where theyve been on my feet.heck I cannot just bin them! Maybe I will need to bury them with a ceremony.
Hi, Codetech — thanks for the tip on the Sony digital camera. That’s good to know.
Yeah, Wamron, I really do like a viewfinder. But, I’ll have to check out the latest in that back window display screen (I always feel like I’m looking in a mirror, it feels like left and right are reversed as I move it or something, the “something” is me, no doubt, heh, heh) feature.
It sure is fun to frame things on the computer — so many artistically pleasing possibilities.
Thanks, Codetech, for the empathy about loving a motor vehicle. Some of them sure are extra special. It’s nice to know others understand the phenomenon. I even weep whenever I read (AndyG, it has been years! #[:)]) about Mike Mulligan and his steam shovel, Maryanne, who tries SO HARD to keep up with that big new diesel excavator. Sure, the artist put a face on Maryanne, but, I can see those faces on machines like her without any aid.
Wamron, just find a quiet corner and KEEP THE OLD SHOES. I doubt, at your useage rate, you will end up with an unmanageably large hoard of them. Now, if you start fondly treasuring all your milk containers …. and empty paint cans…. and… . Might want to ask a friend for help. [;)]
**********
BACK ON TOPIC!
@Mr.. Horsecroft, what a fine response by you. I hope that those other fellows will acknowledge your thoughtful post just above. “IF THEY CAN WADE THROUGH ALL YOUR OFF TOPIC STUFF,” you probably would like to yell at me. {:[)
Janice, I recommend this site:
http://www.imaging-resource.com/
Under “cameras” at top left you will find everything digital made now or in this century described in comprehensive detail.
Wow, Wamron — thanks for the EXCELLENT cameras (and more — neat photo contest winners on “Earth and Sky” — beautiful (most)) site. I was just now reading and researching and realized, “Hey, I’d better acknowledge W’s kindness before ANOTHER half an hour goes by!”
Lol Wamron… some people like holding a giant camera up to poke their eyes into… I don’t. To me the digital back is better because it shows what the image will look like, not what I wish it would look like.
Everyone’s preference varies.. to each their own.
Code Tech.., An eye-level viewfinder can be optical OR electronic. All bridge cameras and now many interchangeable lense system cameras have an EVF which shows exactly the same image as the monitor. Many SLRS now have a live view monitor as well as all Sony SLT cameras. You can use either viewfinder or monitor depending on the situation. But the eye level finder usually wins because it permits you to brace the camera against your head with elbows in and body stable.This creates great stability especially useful with long focal lengths or at night. It also permits you to eye-explore the entire frame to the edges without the least wandering between composition and shutter release. If you want low or high angle shots you then switch over to the monitor. You can if you wish buy an external EVF to fit onto your Sony.
This is partly why I prefer my Sony R1 with EVF to the Sony SLRs I have, apart from its phenomenal lens quality. You DO see exactly what the sensor sees, but in an eye-level finder.
The use of a monitor, on the other hand, echoes the waist-level viewfinders on medium format film cameras. But even then, when not using a tripod it is customary to use a flip out magnifier and place the hood against the eye. As with my Mamiya system cameras. Funny enough, such magnifier hoods are actually made to use on digital cameras that rely on a monitor! Another example of plus ca change.
Then of course, the R1 is designed with the monitor on top to resemble the very same arrangement as on a Hasselblador my Mamiya 645 so the feel of the camera echoes medium format. and I do use that monitor with a magnifier hood, as you would with a Mamiya, a Bronica or a Hasselblad.
Janice…one last point from me on this thread, did you notice they have an item in the news column at that site that mentions Dageurrotypes?
Now I must go and be grumpy somewhere.
Yes, Grumpy #[;)], I did. I was going to mention that to you and forgot. I clicked on it, but, didn’t keep on clicking to get to the actual video — bailed out to go look at cameras. I’ll be returning to that site again and again, I’m sure.
Thanks so much for all your help. Happy shooting!
Soon, I will be Sleepy. 🙂 Not likely to ever be Bashful, though, heh, heh.
(YES, AndyG, I LIKE “Snow White and the Seven Dwarfs — stupid in parts, but, overall, wonderful)
As I said, to each their own. I hate using a viewfinder, and I hate holding a giant camera in front of my face. Some people prefer it. To each their own. The NEX screen folds out and points up or down so you can hold it high or low. To me, for the style of shooting I do, it’s a better way to frame pictures. Of course, what do I know, I’m only currently making a living shooting pictures.
My girlfriend prefers holding the camera in front of her face. It hides her while she’s shooting. She’s starting to realize the NEX is getting better shots since we sometimes go on shoots together.
I would never tell someone blocking their face with a big camera that they’re “doing it wrong”, because I used to use 35mm cameras too. If I need more stability I use a tripod or monopod.