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Forum: Troubleshooting and Beginner Help 09-30-2014, 07:12 PM  
out damned spot! sensor cleaning and keeping it that way
Posted By Imageman
Replies: 12
Views: 1,377
I don't know anyone who has ever cleaned or touched a sensor.

What you can physically touch is a sheet of glass which sits on top of the sensor. I don't know of any sensor that is exposed when cleaning, theyr all under sheets of glass. The topmost sheet of glass is the IR filter and yet another sheet of glass sits under that, the AA filter.

I suppose if you have the top sheet of glass removed when the camera is converted to IR use by IR filter removal, and the second sheet of glass, the high pass AA filter is also removed, you might then be able to touch the sensor surface.

If you have either an AA filter present or an IR filter present or both, you cant possibly touch the sensor, so clean away, we all know how to clean a sheet of glass don't we?
Forum: Photo Critique 09-09-2014, 01:04 PM  
Black & White Monochrome stuff
Posted By Imageman
Replies: 46
Views: 4,701
Ok, I rarely go into in depth dissertations on composition maybe I just don't like rules but I will make an exception. What follows is purely personal and probably worthless.

A subject on the thirds becomes meaningful because of its relationship to the rest of the image. Consider a blank wall and subject on the thirds. The image is meaningless, the blank area means nothing, the image is just a subject stuck somewhere in a blank field.

Not so when you add some detail. Add detail whether blurred or sharply defined and the subject now has a relationship, it becomes meaningful for the subject to sit on the third.

Consider now this image. The crop that has the subject on the third, only can succeed by its relevance to the other details in the image, even though they are blurred. There is another rule, a rule of strength, this rule states that in an image there should be 2 elements only. Element one is subject, element two is ground.

This means a subject well defined, and a ground not well defined. (a well defined ground can become a subject).

Looking at this cropped image with the subject on the third, I see a well defined object sitting in the ground, the bicycle. suddenly the bicycle defeats the rule of subject and ground, you have 2 subjects, the cropping while addressing the rule of thirds has in this image relentlessly exposed the bicycle as a strong element which fights for attention and weakens the composition.

The original uncropped image subdued the bicycle to one of many minor elements and the bicycle was simply in my view a counterpoint within the ground and was not competing with the real subject in that image.

I believe in the original image the blurred objects in the ground although identifiable, served as context for the subject, and moreover showed a world the subject had turned her back on. The world she had abandoned to look at the camera is a rich one, and this original image is a commentary on the photographers art, there is a cornucopia of imagery in the world and the photographer in becoming the recorder of the world, abandons it to become that image recorder. It is a paradox, and this image exposes it.

Not so the cropped image, the detail of the world beyond the photographer is lost and just a bicycle remains. The commentary is lost, all meaning for me in this image is now lost.

I agree it looks more pleasant with the subject on the third, but pleasant contributes nothing.

The original image was obtuse, slightly gritty, disconcerting, and full of meaning. Are we right as photographers to turn away from the world or should we embrace it. Should we be pensive as this photographer in the original image is, or should we participate in the world with joy and exuberance.

This image positively vibrates with significance for the photographers paradox. I love the original uncropped image, with all its foibles and edginess.
Forum: Photographic Industry and Professionals 09-09-2014, 12:28 PM  
A new ''photo'' tool
Posted By Imageman
Replies: 8
Views: 1,095
I use one for street photography and candids, while brushing my flowing locks they have no idea Im taking their picture. Bald tramps do get upset im taking the piss but I merely explain that my hairdresser insists I constantly groom.

I recommend it.

I am also awaiting delivery of the "selfie dunny" a toilet with inbuilt digital camera, for those photographers who only end up with images of ass holes, this new product celebrates the ass hole image. Cut out the middle man, concentrate on ass hole photography.

Its more "fart" than "art".
Forum: General Photography 09-09-2014, 08:49 AM  
No more international warranty card since August 2014?!
Posted By Imageman
Replies: 6
Views: 1,482
if the company no longer supports international warranty you are out of luck whether you registered it or not.

This needs clarifying if you intend to rely upon it for warranty.
Forum: Visitors' Center 09-08-2014, 05:56 PM  
MZ-50 / ZX-50 error codes
Posted By Imageman
Replies: 7
Views: 2,290
sounds pretty terminal, pull the battery and leave it out for a week, then reinsert, also try reset to factory settings (or as close as you can).

That's all I can think.

I have no idea what this error means
Forum: Photographic Industry and Professionals 09-08-2014, 01:41 PM  
what do you do about soreness?
Posted By Imageman
Replies: 30
Views: 3,110
Ive heard of people doing 1000 or 2000 shots in a day.

Photography is not about quantity its about quality. Newspaper photographers on an assignment would come back with 2 exposed images in the 1950s, but those 2 images were both usable. I had a 1 in 2 hit rate with medium format, I had a 1 in 6 hit rate with 35mm, that's 1 good useable image in 6. I still have that 1 in 6 hit rate, yet I see digital photographers who seemingly have a 1 in 1000 hit rate.

A days film shooting used to be 24 or 36 for most amateurs and they would have 6 or 7 useable images in that 36.

Consider this, a digital camera reaches the end of its useful life after 50,000 to 80,000 images despite the claims that a shutter lasts 100,000. That's 160 days use at 300 a day. At 2000 a day the camera will last just 25 days. Doesn't that suggest something is very wrong with these "marathon" shoots. This hobby becomes very expensive when you have to buy 12 cameras a year at 1000 dollars a pop because you are wearing out the equipment prematurely on "marathon" shoots.

I don't wish to suggest you are wrong to shoot 300 in a day, but I will ask you, how many keepers out of that 300 did you get. If you can justify shooting 300 a day by having 250 keepers or more then by all means continue, but if your making yourself ill shooting 300 and most are deleted anyway or never used for anything because theyr not up to snuff then maybe you need a reappraisal.

Rather than trying to find a way of shooting 300 or 600 in a day, maybe it would be better to limit the shots before taking them and maybe shoot 50 high quality keepers.

A publication might use 2 or 3 shots. A sports group similar. Why is 300 shots of one event a good idea. Apologies if I am out of touch here.

I have worked for pay, so I used to be in touch, Jobbing pros get in, take several quality shots, and then leaves to the next job. With 6 jobs a day and a dozen images at each job we have maybe 80 images, and no medical problems.

Im not saying your wrong, im just trying to suggest you might like to rethink your strategy and maybe take fewer better shots, especially if your making yourself ill and wearing out your gear.

I take far fewer images as an amateur I take 6 or 12 maximum on an outing I reject most before pressing the shutter, so I don't have to delete them and I cant understand taking so many. Im just presenting another perspective here.

My experience is after a while rejecting poor shots becomes easier if you choose to go down that route.
Forum: Pentax Camera and Field Accessories 09-07-2014, 09:05 PM  
Questions about the Mechanics of a Variable ND Filter
Posted By Imageman
Replies: 15
Views: 3,838
The circular polarizer is there because the modern camera doesn't work well with a linear polarizer.

A circular polarizer does nothing it simply changes the polarized light that passes through a linear polarizer so the camera can use it.

A circular polarizer is then a linear polarizer and a circular polarizer sandwiched together

To make a variable ND - polarizer you fit a circular polarizer to a lens, and fit a linear polarizer on the front of the circular polarizer.
Forum: Photo Critique 09-06-2014, 11:12 PM  
Black & White Monochrome stuff
Posted By Imageman
Replies: 46
Views: 4,701
Its ok Liney im not upset either and im not being condescending, theres a slight misunderstanding that's all. Were cool.
Forum: Photo Critique 09-06-2014, 10:16 PM  
Black & White Monochrome stuff
Posted By Imageman
Replies: 46
Views: 4,701
ok im sorry for what I said and I retract it totally I was talking rubbish, always follow the rules.

Im sorry I upset you Liney. Ill shut up now
Forum: Pentax SLR Lens Discussion 09-06-2014, 09:43 PM  
Repairing a Plastic Lens Mount?
Posted By Imageman
Replies: 7
Views: 1,749
If you replace the mount with a plastic one be very careful.

Its easy to break the mount where a screw pierces the mount. Its usual for screws to put too much pressure when even slightly overtightened and this causes a fracture at that point.

Don't over tighten, the correct tightness if anything feels slightly slack, you cant run screws up hard on plastic mounts they drill into the mount too easily when you overtighten. Metal doesn't have this issue. Keep checking for tightness to make sure its not working loose.

The significance of the later version using a metal mount is not lost. I think early failures like yours proved an issue and necessitated the replacement of plastic with metal mounts in the later version. If the plastic mount was satisfactory the metal would not have been used they would have continued to use plastic mounts in that model.

Gentle tightening is the key good luck.
Forum: Photo Critique 09-06-2014, 06:42 PM  
Black & White Monochrome stuff
Posted By Imageman
Replies: 46
Views: 4,701
That is not correct, where was I critical of the advice given, my advice simply was opposing it, is opposing advice no longer allowed?

The advice given followed an existing rule, I see much of the advice given in this forum that amounts to following a rule, usually its the thirds rule, and its easy to suggest that, the rule exist and it takes no artistic flair or expertise to state a rule.

The photographer wants advice the image is not following the thirds rule, tell him to follow the third rule.

This advice may well have been good but I see the exact same advice trotted out time after time after time, like a mantra

Picture of caterpillar, crop it so it is on the thirds, Picture of sunbather crop it so its on the thirds etc etc etc.

I simply said following rules slavishly can lead to boring pictures, where is this not advising about the image. if the golden ratio is applied slavishly that may not be appropriate, if a spiral shape is searched for and the image cropped to reveal it that is slavishly following a rule, if three things are revealed by other cropping that is slavishly following a rule. None of these rules may contribute to the image, but they are simple to trot out.

I never criticised the advice given I merely offered encouragement to allow the image to stand uncropped and following no artificial rules, but you read into it criticism that doesn't exist.

I saw a tv program of a possible future and in it pictures were being assessed, they were all assessed using the same rules of composition, and all the pictures turned out identical, the content was slightly different, same subjects arranged in very similar ways all following accepted rules of composition. all were explained as being clever and meaningful, but all were the same.

The artists had long since stopped producing unique and worthwhile pictures because the same rules were used to assess them and unique pictures simply would not sell, so they were no longer made.

Every image I see these days bar a few, have the subject sitting on the thirds, simply because its the rule and feels natural, we have to rigidly crop so every image looks the exact same compositionally. Utter nonsense. Have the courage to defy convention. Look at the very best images of the last 200 years, how many followed these rules, not many.

I still don't criticise the advice, by all means try a thirds composition but do have the courage to be different.

---------- Post added 09-07-14 at 02:51 AM ----------

No problem Liney my own post could be seen as being critical as well, its all about interpretation, and thanks for those kind words recently given, its always hard to offer good criticism and advice, it often seems unwarranted or even harsh, this is a good forum and I think your desire to excel shows and contributes to help it improve as it does with many.
Forum: Non-Pentax: Canon, Nikon, Sony, etc. 09-02-2014, 11:59 AM  
Zeiss Loxia officially announced! 50mm costs $949 and 35mm costs $1,299.
Posted By Imageman
Replies: 25
Views: 3,216
The planar is a classic design and many modern lenses are spawned from it, the tessar is a similar classic design, as is the cooke triplet that spawned most lenses in your bag.

Yes all the zooms that ever have been and all the zooms you use today are derived from the cooke triplet.

The planar and tessar are far from poor relations, a tessar can perform magnificently, and the biotar which is a planar type performs wonderfully well . On the other hand I too am mystified at the price of what is after all a simple lens design. I guess we will have to wait for some images to judge.
Forum: Pentax SLR Lens Discussion 09-01-2014, 10:21 PM  
For all you optical engineers ..
Posted By Imageman
Replies: 18
Views: 2,118
Ok what im seeing is in the case of k10d the limit is the sensor plus AA filter, and the results are fairly flat, the difference between f2.8 and f4 results is around 1.5% which is minimal and explained easily by inconsistencies in measurement.

The k5 results are very interesting they show more of a curve which is to be expected by lens variance at different apertures.

My conclusion is therefore that the k10d results are sensor dependent and are more aligned to sensor resolution limits, and the k5 results more truly reflect the lens performance.

The f stop difference you asked about is likely to be due to differences in data gathering and inconsistent measurement.
Forum: Troubleshooting and Beginner Help 09-01-2014, 09:50 PM  
Why 55mm in the days of film?
Posted By Imageman
Replies: 24
Views: 3,241
This is revealing - "The famous Leica 50mm f/3.5 Elmar lens released in 1920 was a Tessar type lens. After Leica introduced the first 35mm camera in 1925 .... "

This extract says 2 things, first, the very first 50mm lens destined for 35mm format was designed before the first 35mm camera was even built. second, it was a development of an earlier design.

I believe that the decision to go with either 50 55 or 58 was purely based on whatever criteria were deciding factors at the time of design and there was no conscious decision to use one or other focal length. we would have had 57 or 61 if it was convenient to design a lens of those focal lengths. I also believe that having a good consistent spread between lenses was important. Additionally focal lengths were either chosen for a specific purpose or for familiarity or for cheapness. In other words if customers wanted a 32mm they should get one

I think that once the manufacturer had a good range of focal lengths with even spread between them then the company would choose which of its range it would release with the camera.. The deciding factor was almost certainly cost, it being cheaper to make a 50 - 60 mm lens than other focal lengths other than maybe the 135mm.

Typical ranges were 24 35 50 80 135 200 300 400 600

Notice some interesting things, the 35mm was the expected focal length of fixed focal length 35mm cameras, the 35 doubled is 70, close to 80, which is the perfect portrait focal length, 135 was a cheap easy to produce lens and sufficiently far from the 80 to make a good jump, after 135 we return to multiples of 50.

Take out the 35 (which can be seen as a marketing ploy to give photographers used to fixed lens 35mm cameras a familiar focal length). and you have 24 50 80 135 200 400

Portrait photographers could go for 35 80 135. General photographers could go for 24 50 135. Additional longer lengths were handy jumps 200 400 even 600

Notice that the presence of a 55 instead of the 50 makes better mathematical sense, for General photographers, giving 24 55 135. Even 24 58 135 makes sense, there being not much difference between the FOV in each of the 50 55 and 58.

I have no reason to doubt that changing the glass formula allowed different control of aberration and may have contributed to the ability to design better lenses, but the existence of 50mm lenses in 1920 suggests this view is not the entire story.
Forum: Pentax SLR Lens Discussion 09-01-2014, 08:25 PM  
Repairing a Plastic Lens Mount?
Posted By Imageman
Replies: 7
Views: 1,749
I would add that if you are cannibalising a mount, try to find a metal one that fits
Forum: Pentax SLR Lens Discussion 09-01-2014, 08:21 PM  
Mirror Lenses?
Posted By Imageman
Replies: 14
Views: 1,006
Get a couple of long telephoto lenses in m42, a 400mm and a 600mm, they will cost around 100 dollars each or even less.

You will be astounded by their quality.
Forum: Pentax K-3 & K-3 II 09-01-2014, 08:16 PM  
Lenses that the K-3 will outresolve
Posted By Imageman
Replies: 31
Views: 4,953
In film days the best monochrome film would out resolve just about any lens made, and still can out resolve almost any lens made, most monochrome film in general use however was only slightly better than the lenses in general use. Only colour film was out-resolved by the lens.

It was never a problem for the film to out-resolve the lens the only thing that matters is the lens and you want the sensor to out-resolve the lens, you get all the resolving power of the lens in the image. Only in digital has this been raised as an issue and is total nonsense.

Anyone who says its an issue needs his head feeling.
Forum: Pentax Q 09-01-2014, 04:09 PM  
which Q for c mount lenses
Posted By Imageman
Replies: 7
Views: 2,131
As I understand it no cmount lenses are designed for micro 4/3, its usual however to mount on 4/3 to exploit the vagaries of the distortions present, which will be less on q or q7 due to the smaller sensors.

If you want to make the most of the vignetting, the distortions and the aberrations then q7 seems more natural than q, it does depend on the lens though, for example 25mm is the limit on micro 4/3 and vignetting is already becoming apparent, go to 16mm and vignetting is strong, by 12mm you just see a circle within the image. Again it depends on the lens.
Forum: Photo Critique 09-01-2014, 01:36 PM  
Black & White Monochrome stuff
Posted By Imageman
Replies: 46
Views: 4,701
Im surprised to get some of these reactions, I see people following rules for their own sake, and that's not good, I also see good images that follow rules, I have seen rules used to try to turn a bad image into a good one with the idea that following rules is the "secret" to a good image.

Some of you think my opinions are poor, I don't care for personal attacks or the people who make them to be honest so I wont be attacking your image making in response.

We are here to grow, and if I am a worthless photographer I hope to improve and hope to get some assistance, not some kind of fight.

I repeat again, slavishly following rules of composition makes for boring images. Interesting images can follow rules of composition agreed, the rules in themselves don't make an image good.

I like the image as it originally was. For me theres a context in the background that the crops lose. The subject is relating to the objects in the background, but thats a personal view, it might be better cropped to be in the thirds and that's good, also the photographer has a concept that may be better stated cropped that way. It just seems to be alive in its original form.
Forum: Pentax Q 09-01-2014, 01:08 PM  
which Q for c mount lenses
Posted By Imageman
Replies: 7
Views: 2,131
Its usual to mount cmount lenses onto micro 4/3 so why move down from q7 to q micro 4/3 is bigger than either q or q7 isn't it
Forum: Photo Critique 09-01-2014, 11:59 AM  
Macro How did I get this?
Posted By Imageman
Replies: 29
Views: 4,119
My investigation indicates the red channel is over exposed by as much as 4 stops, its impossible to tell how much because it looks like at least half the red has been lost and thrown away. Who knows what was originally there.

To a great extent it doesn't matter, the detail is not separately in the colour channels, it is a mixture of green blue and red channel information. Some manufacturers sample edges data in the green channel (the green channel alone holds 50% of the image details). Other manufacturers sample edge changes from all channels.

So when you desaturate the details appear because most are held in the green channel and just about everything is present in all three channels.

Take test images recreate the situation. take one as metered, one 3 stops underexposed one 4 stops and one 5 stops underexposed. Then in post bring the brightness of all to the same level. Then compare them to see if this effect is reduced as I expect it to be.

Ultimately the workaround is likely to be a mixture of underexposure and some red channel enhancement in post, but lets first find out how much underexposure is needed.
Forum: Photo Critique 08-31-2014, 03:13 AM  
Black & White Monochrome stuff
Posted By Imageman
Replies: 46
Views: 4,701
slavishly following rules of composition makes for boring images
Forum: Pentax Q 08-31-2014, 03:07 AM  
which Q for c mount lenses
Posted By Imageman
Replies: 7
Views: 2,131
You need the largest sensor possible to maximise the c-mount fix.
Forum: Photographic Technique 08-31-2014, 03:04 AM  
Macro Oh dear oh dear oh dear -
Posted By Imageman
Replies: 23
Views: 3,489
I snagged 2 more lenses yesterday ICDWTPOG (I Cant Do Without This Piece Of Glass) got me.

Danger Will Robinson click click click
Forum: Photographic Technique 08-31-2014, 02:44 AM  
Macro Oh dear oh dear oh dear -
Posted By Imageman
Replies: 23
Views: 3,489
LBA Lens Buying Anally, I feel for you
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