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02-12-2008, 11:58 PM   #46
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QuoteOriginally posted by Lowell Goudge Quote
Leo

A star, regardless of the "apparent size" is always a point source and will always be a single pixel. the moon or a planet would be better, since you can see some detail to focus on. and from that point onward, just leave it alone. I doubt the difference in focus from 1/4 million miles to 100 million light years impacts things much.

you should be able to focus manually, or just put the lens to infinity (unless it is defective and/ or focuses past infinity such as a telescope)
Many visible "stars" are not "single points" but are, in fact, double stars, or more, once you put enough magnification on them.... This is clear in many photographs online where a single photograph has stars that appear bigger than others. Not only that, but, diffraction (from the atmosphere) takes it's toll on the light coming from distant stars, and it affects them differently depending on their relative brightness.
Are these "stars" all the same size? Is it because the person is incapable of focusing correctly?
APOD: 2005 October 13 - Alnitak, Alnilam, Mintaka
This is a link to a NASA site's photo of the day, so it was probably not shot by "amateurs", even if it wasn't captured by NASA itself. To me, this photograph has big stars, and small stars. Some are more than one pixel wide. None are very big, but some are (apparently) bigger than one pixel, certainly bigger than others.

I agree 100% with Leo that I look forward to the live view features in the K20D for astrophotography. I think it's going to be a great boon to how I actually use my Pentax camera. In fact, it's probably about 50% of why I am looking forward to buying a K20D.

You _should_ be able to focus manually or put the "lens" to infinity, but that is either impossible because it's a telescope and has no "infinity" or because the darn viewfinder is so dark that in-focus and oof are not really that different in the (DARK) optical viewfinder. (and I've found that to be true, even with my 50/1.4 shooting constellations like Orion.)

I will welcome the availability of live view, even if I don't plan to use it for 90% of my "terrestrial" photography. But like many technological improvements, it's frequently difficult to envision how you could use a new technology until you actually have it in your hands, then after that, it's difficult to imagine living without it.

I also think this will make the Pentax DSLR camera more tempting to people coming from P&S type devices, and I think that will benefit Pentax as a company directly, and me as a person who has bought into the Pentax system, indirectly.

-Chris

02-13-2008, 05:20 PM   #47
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Lowell,

Falconeye and Chris are absolutely right about focusing on stars. Though a star is a point source in outer space, our photographs through Earth's atmosphere show stars to be anything but a single pixel. In fact any bright single pixel is likely to be a flaw! For example my latest photo (same Flame and Horsehead area as Chris' example) has stars ranging from 120 pixels (Alnatak) to 6 pixels wide. The brightness is roughly a Bell Curve and the steepness of the bell indicates how steady your sky is. Here is Connecticut stars are always a wider blob than Hawaii or Chile where the pros have their telescopes. Why are the best telescopes there? To get closer to single point star images!

In the 14 months I have been using a DSLR for astrophotography I find looking through the viewfinder focus is problematic. What looks to me to be sharp won't look so good when I bring the PDF file inside to process with astro software. So I'm back outside to adjust focus again. Putting the lens at infinity (if I'm using a lens) is nowhere near accurate enough.

Falconeye, I have a RoboFocus on only one telescope. With my SBIG camera I can use the PC to focus that scope automatically.

Pentax has never supplied a K1x0D supported version of Remote Assistant. They support the istD and K10D only. The istD version does work, sort of, if I avoid setting anything from the software. I have used it to focus my astrophotos by setting exposure etc before connecting the camera. It is still iterative, click Remote Assistant shutter button, wait for 10 MB download, switch to Pentax Photo Browser to see the dot, adjust focus knob, repeat 10-20 times. With Live View I could stand by the scope and adjust the knob and see the results on the computer screen in real time.

So far I have not found any astro focusing software for Pentax, only the, "Big Two" cameras and true astro cameras.

No, I won't buy another camera just for live view but I do wish I had it!
02-13-2008, 09:09 PM   #48
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At first I thought of live view as a cynical means of attracting people used to digital point and shoots to the DSLR market, but after playing with the Canon 40D it does offer some advantages to serious photographers in specific situations.

As has already been pointed out, live view is useful in astral and macro photography where focussing has been difficult with traditional methods. In addition to being able to bring up a real-time preview on your computer, you can digitally zoom in on a specific part of the image to tweak your focus, ensuring the image is sharp. It's like having an extreamly powerful viewfinder magnifier that you can move about the image.

It's also very useful in collaborative situations. When working with a makeup artist or a lighting assistant, having a live-view image handy for all to see makes it a lot easier to communicate with your teammates, as you can gather 'round the laptop and discuss the image. I'm sure there are experienced photographers out there who shudder at the thought, but this has long been commonplace amoung motion picture directors who need to communicate with their team. In a professional situation, especially when everyone's getting paid by the hour, it can make things run a lot smoother.

Also the live view feature on the 40d makes the camera much quieter, since the mirror isn't flipping up and down as the shutter opens and closes. I could see how this feature might be attractive to nature photographers trying not to spook animals. I imagine the K20 will be similar.

Finally, there's an additional advantage for Pentax, Sony and Olympus users. Since the image stabilization systems are in the bodies and not the lenses, its effect isn't seen through the viewfinder, forcing the photographer to simply take the camera's that it's working. It's a minor problem, but live view solves it.

The arguments against live view that I've seen on this forum are rather trivial. Nobody's forcing you to use it, and nobody's going to take your viewfinder away. The added cost of the camera is almost an abstract, meaningless concept since, as anyone who's studied the advertising field knows, retail price point is usually determined by marketing people, and has little to do with how much a product actually costs to manufacture. Even if that weren't the case, the cost of adding live view would at least be offset by the cheaper CMOS sensor (vs CCD). And besides that, your camera is already loaded with features you paid for but never use, so what's one more?
02-13-2008, 09:52 PM   #49
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QuoteOriginally posted by Peter Vesuwalla Quote
the live view feature on the 40d makes the camera much quieter, since the mirror isn't flipping up and down as the shutter opens and closes. I could see how this feature might be attractive to nature photographers trying not to spook animals. I imagine the K20 will be similar.
The Canons have live histogram, contrast detect focusing avoiding these mirror flips, and exposure simulation for your collaborators to discuss what the scene will look like.

The K20D was specifically designed with none of this.

02-13-2008, 11:02 PM   #50
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QuoteOriginally posted by falconeye Quote
In astro photography, one is always focusing on stars. Normally, the image of a star never is a point because there is no such thing as an ideal telesope. In focus, you see a star as a tiny dot surrounded by a first or even second circle of refraction. In order to focus, you try to achieve to get such an image as much as possible which can be terribly hard. Out of focus, a star looks like a disk.
try using a Hartmann Mask How-to Make a Hartmann Mask - How To
Also Focusing Methods

Last edited by pixelsaurus; 02-13-2008 at 11:09 PM. Reason: Additional info
02-13-2008, 11:03 PM   #51
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QuoteOriginally posted by falconeye Quote
Don't you have a PC-controlled focus motor on the telescope?

If you had, using Pentax Remote Assistant (don't know for K10D, I use it with *istDS), one could remotely shoot, evaluate and correct focus from the notebook. One could even write a small program which automates the process to some sort of contrast maximization.

I confess I did not try it yet but I am thinking I may do so.
Please tell me your secret. My *ist DS only half works with Remote Assistant.
02-14-2008, 06:17 AM   #52
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I really don't understand all this angst re Live-View. It's just another feature on the camera. No more no less. If you do not want to use it then do not enable it. There is no extra cost as this feature is essentially a "freebie" with the CMOS sensor. I'll probably not use it very much when I get my K20D ... well, maybe for macros when the camera is mounted on a tripod.

There are several features on my K10D that I haven't used in the 10 months I've owned the camera. Who knows, maybe someday I will have a use for them.

A couple years ago I purchased a Minolta A2 ... nice camera with a lot of photographer oriented features. This puppy has live view 100% of the time. Works fine. Love the real-time histogram.
02-15-2008, 07:03 AM   #53
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have over 10 slr cameras. Everything from 110 to 5x7" (Graflex). Love slr viewfinders. Also see uses for live view. Some not mentioned so far.
The midwest USA had a major ice storm this week. Many people are without power 5 days later. Was one of the lucky ones with power so went out shooting. It was 16f out. Half the time I brought the camera up to shoot the viewfinder would fog. Couldn't see to focus or compose. Even holding breath didn't stop it. Don't think using a right angle finder would help. Reached in the bag for the Olympus E330. It also fogged up. Hit the live view button and with camera 1.5 ft away- no problem. Score one for live view. Also used the Pana LX2 P&S with no problems.
Besides the macro and astrophotography benefits liveview is a boon for underwater photography. Put on a scuba mask, place camera in housing, and tell me how much of the slr viewfinder you can see. Not much.
The Olympus also allows one to liveview in B&W (with 3 different filter effects). This is a big help to visualize a B&W photo. Don't tell me thats only for P&S people. Fred Picker at Zone IV used to sell a viewing filter to help film shooters do this. He was as exacting as they come. Even modified handheld spot meters to be more accurate. Don't know if this would work with the Pentax since previous cameras have you convert shots later. Can't wait to see if this will work for real IR photography. SLR finder is pretty useless with that dark filter on. Always loved rangefinders for that. They have advantages over slrs too.
The Oly dioes have some advantages over the Pentax. The screen does articulate. This allows one to use a waistlevel finder. You don't have to hold it at arms length to focus so shots can be just as stable as with camera against face. You get nice perspective on people and other subjects. Had a Yashicamat twin lens. Loved/ hated it. Loved big viewfinder hated the fact that everything moved in opposite direction when framing. Thats gone with articulated liveview.
Live view does make a camera slower- some times. Don't know of a slr that can do 20fps like the K20D. So liveview can also make a camera faster.
Some are saying photograhy should be a painful experience. Fine. Then you should put down the wussy digital camera and lug a 16x20 view camera around with glass plates. No convenience but better quality and a lot more pain. Even better, forget photography and chisel on the old cave wall.
Liveview is the future. It will not replace slr viewfinders anymore than P replaced M on the exposure dial. It is virtually free. Love it on the Olympus. If you don't find a need for it out of all these posts perhaps you are in a creative rut and need to explore other types of photography.
thanks
barondla
first batches of K20Ds are arriving in about 1.5 weeks. Can't wait.

02-15-2008, 10:11 AM   #54
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QuoteOriginally posted by pixelsaurus Quote
Please tell me your secret. My *ist DS only half works with Remote Assistant.
Its propbaly the same half than mine

I download photos to disk to look at and manually turn the focus knob. Still much better than do it at the camera. Turning the focus knob is subtle. Engaging image review in magnified view would be a heavy touch for a scope-mounted camera...

I wonder if RemoteAssistant with a *istD shows sort of LiveView on the computer screen as the RemoteAssistant GUI would suggest. And if it supports remote manual focussing...




The comment on LiveView with Canon 40D took it for granted that LiveView would imply
LiveView on a USB-connected computer as well. What do we already know about the K20D here?
02-16-2008, 08:55 PM   #55
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Peter Vesuwalla,

Good point about the 40D holding the mirror up, I understand it can quietly take 100s of rapid images of the Moon and bright Planets without vibration.


pixelsaurus,

I've tried Hartmann Masks off and on over the years. Some seasons it is hard to find a star bright enough for the viewfinder, with a mask the "two" stars are even dimmer.

I'm surprised Remote Assistant has a problem with the istD, version 1 was written for it. My K110D once decided not to work with R.A for over a month, then recovered. My K100D always worked but both cameras have issues... I find getting P.C. software from a camera company to be problematic.


barondla,

Thank you for several more examples of occasions when Live View is useful.


falconeye,

I engage image review and zoom between exposures, doesn't seem to bother scope or camera. The 2 second mirror up delay allows vibrations to settle when I take the next image.

Remote Assistant with the K110D lacks any means of viewing repeating images (say, every 3 seconds). My timer could cycle the camera but the shutter button aand jack go dead when connected to a PC.

It would be a boon to focusing if R.A. could display repeating photos (say every 3 seconds). It has a timer but Photo Browser must be manually advanced to the next photo. (Unless someone has found a way to do this ).

Since I started astrophotography with a K1000 borrowed from my wife focusing has always been a challenge. Live View would help a lot.
02-16-2008, 10:37 PM   #56
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i hear ya almost all the way! i would rarely, if ever, use live view. i think that pentax should have put their innovations elsewhere, at being the first in something else for the k20d.

the k200d, on the other hand, rightfully deserves live view, as it is designed for beginners. but unless you are a macro photographer or do a lot of weird positions with your camera, you do'nt need live view. (just my opinion!)

i was wondering the same thing just a few days ago hehe i'm with you 95% of the way!!
02-17-2008, 08:32 AM   #57
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QuoteOriginally posted by mutley Quote
The Canons have live histogram, contrast detect focusing avoiding these mirror flips, and exposure simulation for your collaborators to discuss what the scene will look like.

The K20D was specifically designed with none of this.
Hi Mutley,
As far as I understand only the very latest Canon (450D / XSi announced at PMA last month) has contrast detecting focusing. If even the mighty Canon corporation takes this long to develop that feature, then it is not hard to see why Pentax might take a while yet to get it working.

True that the Canon 40D has a live histogram, but the Nikon D300 does not. So, again, that shows how that is a feature is non-trivial to implement. Canon choose to send money on getting a live histogram working first, while Nikon spent the same amount of money/engineers on getting contrast detecting autofocus working first, and Pentax didn't spend any money at all

As for exposure simulation: can't the K20d do this? Surely, you will be able to adjust the aperture in manual mode and watch the live view image get darker/lighter and get more/less depth of field, right? How could Pentax design a live view system that doesn't do this?!
02-17-2008, 06:04 PM   #58
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As well as a Pentax K10 and a K&M 7D I have a Sony R1, which has live view using the viewfinder or monitor.

The attached jpeg shot was taken last Thursday using live view to adjust. The cop was only there for a few seconds, just as I shot he moved.

I used minimum post processing in iPhoto 08.

Live view makes it easy to see what one is getting, it was great having it for this early PM shot.

Rg.

02-20-2008, 04:38 PM   #59
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Suffering for the Art is part of the experience (getting dirty). Aside from having to put the camera between forking points or in an entwined mess of barbed wire live view is pointless or more of a viable option while using a remote at a glance distance. That's just my own personal preference.

Live view would drain the battery faster. It has some uses, but there are other improvements that should be more of a priority as features. Peter V makes some great points.


Yes, I've done the barbed wire thing back in my film cam days.
02-21-2008, 02:55 PM   #60
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QuoteOriginally posted by Rickster Quote
I really don't understand all this angst re Live-View. It's just another feature on the camera. No more no less. If you do not want to use it then do not enable it. There is no extra cost as this feature is essentially a "freebie" with the CMOS sensor. I'll probably not use it very much when I get my K20D ... well, maybe for macros when the camera is mounted on a tripod.
I'm just worried about them making compromises with the still photo quality to incorporate things like live view and movie mode. Plus it will probably lead to even worse viewfinders on the lower end DSLR's. I'd rather see the research effort put into lowering noise and increasing DR.
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