james_oneill

If you've taken steps to make everything else rigid at best it is redundant, at worst SR allows the sensor to move by a tiny amount which can take the edge off the sharpness.

 

Someone on the DPReview forums asked about battery life, and John Carlson, from Pentax US, said it has no noticable effect.

 

At the highest shutter speeds it can't be effective because the acceleration and braking forces on the sensor would be too great, but I don't see any need to turn it off.

Seems like a combination of more IR filtering on the sensor and a lower natural ISO. This one http://www.photo.net/photo/1425347 won a competition a couple of years ago which was a digital IR with my compact. I tested the *ist-D with an IR filter but only ever took a couple of pictures with it.

I don't need to know if someone liked it or not. What I want to know is why they liked it (or not).

It depends where you are.

 

Under British law there is no requirement to get a model release for anything (though it is still good practice to get one for non-news usage).

 

Depending exactly where you are in the world the law WILL vary. A test for "can I put it on P.n" would be 'could a newspaper run this picture', stock photo agencies will have tougher requirements, but if you have pictures you think they might want, talk to them - they should know the legal position.

Sorry to go deep for a second.

 

A couple of weeks back something on the Radio refered to "The Structure of Scientific Revolutions" by Thomas S. Kuhn. I haven't read it, but did pick a summary ... One of things he said is that a scientifc community is based on is a set of beliefs, methods terminology etc (Paradigms) and he quoted Max Planck "a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."

 

I was talking about how someone was seen at work, and this would only change if the people that held a view of them died - or at least moved on. There were a set of entrenched paradigms about this person who had committed repeated heresy - questioning the Paradigms on which their management worked. If you don't share the paradigms you're not part of the community and in that case ...

 

Why should this be unqiue to scientific communities - if it applies to work places, why not communities of photographers ?

I have the SP 90mm as well. <p>

 

You can change the mount to a Pentax <b>KA</b> mount and then it works in all exposure modes (Program / Shutter / Apperture). <p>

 

With the K mount (not KA) there are no electrical contacts for the camera to understand the apperture setting. You have to set the apperture manually, tell the camera from the menu that is OK, and then press a button to get the camera to stop down and take meter reading and set the shutter speed for the chosen apperture. <p>

 

Obviously KA is more convenient - I had a K on my Tamron and changed it. Going rate for mounts is about $20 US, I actually sold the K for a fraction more than I paid for the KA. <p>

 

Here's an example <a href="http://www.photo.net/photo/2492657">From my Garden last summer</a>

No personal experience (I have the Zenitar on my *ist-D); there are some threads in the forum on dpreview <a href="http://forums.dpreview.com/forums/forum.asp?forum=1036">http://forums.dpreview.com/forums/forum.asp?forum=1036</a>

just goto search and put in Peleng.

1. Why the fuss about the 5D ? It's full frame but Canon have had the 1Ds out as a full frame camera for ages. The MKII has been out for months. The 5D is lower res and not much cheaper. It also costs double what a 20D costs, which is double what 350D costs. How many do you think Canon will sell of each ? (Answer if they sell 1 5D for every 100 350Ds I think they'll be delighted) What do you think the market is for a $3,300 Pentax body ?

 

Long term full frame is the future at least for upper-medium DSLRs - because adding Pixels to todays 6 and 8MP APS-C size sensors won't improve image quality much - we're at the sweet spot, sensor res matches lens res (5MP + compacts with small sensors are lens bound, Old 3MP DLSRs like the D30 didn't have enough Pixels). Increase resolution and we'll get more noise, less dynamic range and little increase in recorded detail. But APS will always have a price advantage so may well remain in Entry-medium DSLRs.

 

I wouldn't get rid of any lenses until you no longer have an APS-C sensor body to fit them to.

Jerry, just ask anyone who ever posts a nude.

About 1/3 of the people rate the picture on merit. 1/3 inflate the score for anything with breasts in it, 1/3 reduce marks.

Those people who are interested in say eveything except macro (how many insects can you look at ?) don't want to select every other category in turn.

 

It would be nice to see who had given what rating - but when we had that Brian had to deal with so many complaints of revenge rating that it became unworkable. It would then be nice to see on someones profile page the average score they had given split by category.

Aesthetics is normally how much you like looking at something, but if you want to use it better for photo.net use it for "Visual impact", there are pictures which deserve a good score even if you dislike them because they are really arresting. Taste does come into it, but it shouldn't - so does subject matter. I get marked up and down by people who either like or dislike my choice of subject matter. Both are bad raters, although one flatters my ego.

 

Originality - I use for the quality of thinking that went into a shot where 1 is same old cliche / no thought and 7 is very well conceived and thought about, even if it is a cleaver copy of something done before (because most things have been done before). If someone posts a shot of an insect or a flower in a "hey I got a macro lens but can't think what to shoot" way then give it a 2 or 1 for orginality. But if it is a good enough picture give it 7 or 6 for Aesthetics.

 

Technical quality: a blured or grainy image can add or subtract from it's Aesthetics, or perhaps add to its orginality.

 

Requiring comments just makes people post "Great photo" or "Garbage" without telling the photographer much. Good manners says post a comment when you feel you have something to say. People like comments more than scores in my experience.

It depends on the type of batteries. Lithium CRV3 or AA (single use) batteries will give you in the region of 1000 shots. (Pentax claim 800 in the *istD manual but that seems to be pessimistic)

NiMH will give you about 1/2 of this (Pentax claim only 400, I've done 375 RAW files in one shoot, and I'm getting well over 500 before the batter waring comes up.)

 

External flash doesn't affect battery life. Pentax's numbers suggest if use internal flash for all shots, reduce the numbers by about 30%

 

Note that Lithium actually have a lower mAh rating, but they will give all their charge before the voltage drops to a point where the camera no longer works. NiMH still have something left in the tank - you can actually use them to drive an external flash for quite a few shots (I've read reports of 100+). With Lithiums, when the camera says they're dead ... they're dead

<i> Given a population, the mean for any subset of it is going to approach the mean of the population as a whole as the subset increases in size. </i><br>

ONLY if the population is randomly selected from the population as a whole. If you take "basket ball players" as a population and compare them against the height of population as a whole.... <p>

 

 

<i>The only reason I have to think that the average intelligence might be higher is that education level of the photo.net audience is pretty high on the average.</I> Photography (and internet use) are less widespread among poorer people, and income correlates fairly well with intelligence and education. [Not all poor people are stupid and ignorant, but very few rich people are]<p>

 

<i>On the other hand, the population is 80% male which, according to my wife, is a negative factor for intelligence. </i> I found my IQ apparantly dropped 10 points when I got married. It's dropped a further point per child per year since I became a father.

As someone who posts nudes, I am convinced that there are people who both "up-score" and "down-Score" nudes based on the fact that they ARE nudes. If I post a picture which deserves a 5.0 there will be a couple of downraters who pull it down to 4.0. If I post a picture that deserves a 4 there will be a couple of upraters who boost it to 4.5.

 

Both sets of people annoy me, because I'd like to know which of my pictures are better or worse and allowing both sets to hide behind anonymity seems to have made things worse. Of course they both believe that their actions are needed to cancel out the behaviour of the other group.

A movie is a different thing to a photograph - movies, plays, ballet have a time dimension that a photographs, paintings and sculpture do not. A photograph just IS. It records a moment ...

Movies have story to tell, even news shows an event as it unfolds. The photography can be very good (someone has already mentioned Peter Jackson) but it is subserviant to the story - the cinematography can't upstage Lord of the rings.

So there is a tension between the role of the director as teller of the story, and the role as creator of great images (which is more of a team effort led by the director in any case). I don't think you don't have to be great image maker to direct good films. I give a photographer of stills a better chance of switching to movies than the other way round.

<i>Now people complain because they can't figure out who gave them a "low" 3, 4, or 5 rating in the RR queue which "spoiled" the nice 6 average they would otherwise have had on their photo.</I><br>

Courtesy of their mates... Though frankly if I mark someone as interesting because I like most of their past work, then I'm likely to give good scores to their future work <p>

 

 

<i> People say that it is important to them to be able to "validate" these low ratings by looking at the portfolios of the people who gave them; it doesn't seem to occur to them that the ratings might be valid just because the rater was a human being with functioning eyes.</i><br>

Humph. I didn't care about the pictures someone has posted. But if I look at their top rated and find it's all "Raindrops on roses and Whiskers on kittens" and they give some moody art-nude of mine a 2, well I can understand it - they just don't like my kind of picture. <p>

<i> And, strangely they never complain about how the non-anonymous 6 or 7 ratings they've been getting "spoil" the 4 to 5 average that their fairly average photo would otherwise have.</i>

Actually anonymous 6 or 7s annoy me just as much. Again if I can see someone's top rated and they're all nudes then I can see if they belong to the "add a point for each visible nipple" school of marking. I'm not interested in their scores - flattering as they are to my ego.

Now before I could track people who had scored more than one picture of mine - I had every score in a database and I could say "taking the scores of people who have rated more than 4 of my pictures, which are the best and worst". Who constantly rates my pictures higher or lower than the average ? And so on. <p>

 

<i>So, the measure of success isn't how many people we have singing the praises of the system in this forum.</i><br>

It might be worth having a whole other forum for the rating system. That would make it easier to filter it out. However the less useful rating system was the main reason I haven't renewed my subscription, and why I use the site a lot less now than in the past.

Some thoughts in no special order. <P>

 

Except that is the sort of puff piece which you get in the Saturday Grauniad* <p>

 

Digital doesn't really change much in the picture making. Cameras (digital or otherwise) don't tell you what to photograph, where to stand, when to take the picture, how to set up lighting. The notion that <i>Amateurs with artistic pretensions may soon be buying aesthetic software, inserting a Cartier-Bresson chip to guarantee that shots come out as "decisive moments", </i> is tosh - beyond the dreams of the most ambitious AI researchers. <p>

Putting a camera in a device we cary with us <b>IS</B> a siesmic change. In 15 years hand held phones have gone from zero to ubiquitous. It's possible to embed a (poor quality) camera in a phone - the thickness of the phone set lens to sensor distance (focal length), and from that comes sensor size .... a device with a good camera embedded in it is a poor phone. <i> Photojournalists now find themselves upstaged by amateurs, who just happen to be on the spot of some catastrophic event and are eager to share "breaking news" with millions</i>. Photo-journalism is more than being dispatched to record the scene of the latest train wreck from a distance. Those kind of unfolding events had been and gone before the hacks got there. Just as the mobile phone has allowed people caught up in these events to phone the news media to tell their story (surely a journalist's job) so the camera phone allows those same people to show their story. <p>

 

The fact that some people can produce a decent picture (at least for on screen work) with a camera phone doesn't prove much. You can produce far better pictures with a disposable film camera - a 10x8 print from most phone cameras looks pretty poor, resolutions will increase which makes the image less pixelated, but resolution [detail resolved] won't - the mushy images produced by a tiny lens working onto a tiny sensor will be recorded with higher fidelity. Don't knock the phone camera ... millions of extra things will be recorded but that doesn't make a great deal of difference to comerical or artistic photography. It might mean wrong-doers get brought to book who wouldn't or lives get saved - I read a report of guy who found a snake in a box of imported fruit, he photographed it with his phone and while trying to remove it, it bit him. The snake was identified from the picture which meant he got treatment for a bite which could have killed him. All hail the omni-present camera ! The picture will not be in any galleries :-) <p>

 

 

<i>"But for serious young photographers about to embark on careers as artists, such widespread democracy poses a threat. What room in this everyone-is-a-photographer-world, they may ask, can there possibly be for me? "</i> Indeed what room has there been for painters for many years where anyone can go out, and for modest outlay buy paper and paint - or worse a pencil and sketch ? <p> Some while back I said that I could be taught to put paint onto canvas in exactly the same way that, say, Monet did. Would that mean I could paint a monet ? Hardly. <p>

 

Digital changes distribution. Any idiot can have a blog, a photo-blog or post pictures to photo.net. Here is the "democracy" that the writer speaks of. No longer do you need the patronage of a gallery or a publisher. For less then Van-Gogh spent on paint you can show work to the world on the internet. And while people had to go to gallery to see work, a link can be passed and work viewed from any place - physical location doesn't matter to the internet. <p>

 

 

 

* Footnote. The "Guardian" newspaper is still refered to by many in Britain as the Grauniad - a reference to the paper's terrible typos from a era when unionized newspaper printing didn't allow for a spell checker to actually check spelling. A spell checker would have been a person, likely one who sat in a fleet street pub claiming tripple overtime.

<I>Sturges criticizes the arbitrary division of people and their bodies into sexualized adults (over 18) and supposedly asexual children (under 18). The question really is: Should tasteful, non-exploitative erotic photography of adolescents be allowed? Is such a thing even possible? </I><p>

 

Hmmm. This is difficult territory. I can see beauty in some of those pictures. I've always said there is nothing wrong with a erotic photos if the people in them consent to be in them, and the use they are put to and understand what that means. The 18 division is one of saying "above this age it is safe to assume people understand what they are doing, and below it one can't even though many people can understand this well before 18" the photographer can't be the one to decide. It's impossible to frame laws which allow <i>tasteful, non-exploitative erotic photography of adolescents</i>but ban the tasteless on exploitative; so it is generally accepted that one does not erotic pictures of adolescents at all. <p>

 

There are some great photographers there; but sometimes I too find the great names are not inspiring.

I'd love a full frame sensor, but the technology is still too expensive.

 

Speeding up the memory card interface would be good, but there is still time needed to process the image before it's saved.

 

I've got the *ist-D and I think the user interface is better than any camera I've seen -the only change I'd like to see is for the ISO to be displayed.

 

The write to CF speed on the D is too slow. A bigger buffer wouldn't hurt. It would be a smart thing to let it use both CF and SD. I want a faster interface because the USB 1.1 on the D just doesn't cut it

 

I'd like a standard USB connector (with the ability to draw power and charge the battery - so we can loose the DC in socket). I'd like the remote release / usb / video / and X-sync connector to have a single good quality cover over them. That's the only gripe I've got with the body - those rubber covers don't inspire confidence.

 

If they come out with an 8MP *ist-D with USB and a decent write speed I might buy one ... but I'm expecting to wait for the next generation - 11MP full frame I hope.

I use a Tamron 90mm f/2.5 SP on 35mm Film, and a Pentax 50mm f/1.4 (75mm Equivalent) on my digital (APS-C Size).

<i> since 9-11 there is a sweeping paranoia at large, fueled by no less than our Executive Branch. Therefore let us take some measures,and perceptions of the truth and I bet if you asked: Is the world more dangerous and scary than when you were a kid that 75% of respondents would say "Yes."</i><p>

 

That's my point. 9-11 was very high profile, and the world is not very much more dangerous. Look at the number of people who stopped flying post 9-11 but in September 2001 you were less likely to die in a plane crash than you were flying in the 1950s. Take the number of people who died in those attacks, and work out how it takes that number of people to die on the roads, work out how long it takes that many people to die of hunger and preventable disease in Africa. A dreadful event like 9-11 is so traumatic that it distorts the perception of the world.

That's how a newspaper might put it.

 

Here's an example. In Britain, the number of children murdered each year has remained about constant since victorian times, although the population has increased. When I was 7 and 8 years old I walked to and from school alone and many other kids did the same. These days fear of abduction (etc.) that come from reporting of some dreadful means parents simply won't allow it. The risks haven't got worse, but we have a greater awareness that there is a risk.

The apperture is the same regardless of the distance from the film - so there is no diffraction impact. However there is an effective reduction in apperture ...

How so ? f stop is focal length / apperture diameter. A 50mm lens at f/2 has a apperture diameter of 25mm, at f/4 it's 12.5 mm and so on.

Similarly a 100mm lens has 50mm and 25mm appertures at f/2 and f/4

 

The brightness of the image is a function of the AREA of the apperture and the square of the distance from the image (move the lens twice as far away the light has to cover 4 times the area).

 

When focused on infinity a 50mm lens 50mm away from the image, and 100mm lens is 100mm. So the lens needs an apperture 4 times the area since the 100mm lens has twice the diameter for the same f stop it has 4 times the area. So f/2 or f/4 give the same image brightness regardless of focal length. HOWEVER this only works at infinity. If you put 50mm of extension onto a 50mm lens you've doubled the distance to the film so you need 2 stops more exposure than an off camera light meter would tell you.

 

As for DOF here are 3 equations.

 

Hyperfocal distance = f^2/c*a

f = focal length

c = circle of confusion (0.03mm for film, 0.02mm for digital)

a = apperture (f stop)

 

For a 50mm lens at f/8 on film h = 2500/ 0.03 * 8 ~ 10m

 

for a focus distance d, far point is given by

d*h/d-h

and the near point by

d*h/d+h

 

You get a life size image when d=2*f, (0.1M for a 50mm lens)

 

so the far point = .1*10/10-.1 = 1/9.9 = 0.1010m

and the near point = .1*10/10+.1 = 1/10.1 = 0.9901

 

So focus down to 10 cm and you've got a d.o.f of about +/- 1mm (9.9 cm to 10.1 cm) compated with 5m to infinity at 10m

Got the 90 f/2.5 SP on my *ist-D. Example <a href="http://www.photo.net/photo/2492657">Here</a>

 

I had a "spot" problem on a studio shoot recently with this lens (only) it went after I cleaned the lens and I just did a test shot at f/13 and it's fine. When I looked more closely at the lens I can see some other spots in a line which make think it was a flare problem caused (or worsened) by the lens.

 

The lens is easier to use if you have the KA mount than the K on Pentax digitals

I'm sick of these things. On Windows XP SP2 Internet explorer has an option to disable Add-ins (tools/internet options menu, programs tab manage Add ins button). So I have disabled Flash which is almost always the culprit. I've also told i.e. not to animate GIFs, and I've put entries in my hosts file to break links to the worst companies that pollute our screens (doubleclick).

The cable is not quite standard. Nikon use the same one which you should be able to find on-line without too much difficult (I just put in mini usb cable on google). Worth a quick call to your local pentax service department, because they should keep these sort of things.