Forgot Password
Pentax Camera Forums Home
 

Showing results 1 to 25 of 300 Search:
Forum: General Photography 4 Days Ago  
Your "minimum kit" per purpose
Posted By Bob 256
Replies: 28
Views: 733
Going on a trip that includes air travel on short notice so my "kit" involves: 1) My K-1 camera; 2) A Pentax 28-200mm zoom.

Granted this is for general picture taking tourist style photos.

I anxed over what to take but only two carry-ons allowed (one is my laptop which serves as my workspace) so with my lightweight clothes bag checked (at $25), I finally settled on a minimal "kit" which will suite a good number of shooting requirements but not all, and certainly not to the quality I would like (well, the K-1 isn't a problem). Could have been worse had I been forced to take only my shirtpocket camera. Airlines have got to start lightening up (and I don't mean making people lose weight to get on board)!:fedup:
Forum: Photographic Industry and Professionals 6 Days Ago  
Looking for a Photo Service
Posted By Bob 256
Replies: 9
Views: 299
You never know where those SWAGs are going to take someone. I was going to build a contraption very similar to what your site offers - Arduino control on the steppers and also using the micro-controller to read a bitmap file from an SD card for controlling laser firing to blast the photoresist directly (might have to tame a 1 Watt + laser). Some technical issues with the arrangement in terms of spot size and power that have to be worked out. Having a fully assembled unit would save some time so will look into it for sure.

Boards are always available and I can coat them myself if needed so those materials won't be extinct for a while.

Thanks again SSGGeezer.
Forum: Pentax Price Watch 6 Days Ago  
128GB PNY SDHC UHS-1 U3 type SD card for $39.99
Posted By Bob 256
Replies: 6
Views: 322
When I pulled up the site, it listed the item for store pickup only. Not too good for me but looks good otherwise.

You could have some issues. You can put an older card in a newer slot, but the other way around is not approved. You can try it and if it works, you probably won't have any corrupted files, but as you mentioned, "probably" shouldn't be counted on.
Forum: Photographic Industry and Professionals 6 Days Ago  
Looking for a Photo Service
Posted By Bob 256
Replies: 9
Views: 299
AstroDave: I think a good ink jet pattern would work better than a pen plotter. Around here, a pen plotter (and its pens) is about as hard to get as a box of Kodalith. All my patterns are in regular image formats and they would need to be changed to vector files - just not too practical if I can get them to film instead.

SSGGeezer: A bit harsh for etching the thin copper film on a printed circuit board. They actually have x-y router systems for that purpose, but they take forever to route a single board and require vector files to work. Ofttimes, I make multiple boards (the same), and a photo process is real quick at that. I did, however, look at the Bang Good laser engraver and it might work as a direct to board writer for the photoresist. It uses a blue laser and that could probably be pulsed on a pixel level to get what I want. Will explore that one further - and the price is right. Thanks for that tip!

I might just farm out my board making to one of the firms that does that - a few around. Would have to overcome the raster to vector graphics issue in that case.

Thanks anyways folks for all the suggestions.
Forum: Photographic Industry and Professionals 6 Days Ago  
Looking for a Photo Service
Posted By Bob 256
Replies: 9
Views: 299
Thanks AstroDave. I've tried that but the results are disappointing. I actually got better results from an inkjet print on film than with a laser printer. The resolution is adequate, but laser transparencies tend to have a lot of pinholes and often aren't dense enough which leads to poor patterning on the photoresist. I probably was spoiled by the results I got with film since they usually provided excellent results with little effort. I appreciate your offer though. I'm contemplating building an x-y scanner which would print directly to the printed circuit board from a file - just haven't had the time yet. Would hope that there is still a shop out there which could print to film products litho or azo.
Forum: Photographic Industry and Professionals 06-12-2018, 12:00 PM  
Looking for a Photo Service
Posted By Bob 256
Replies: 9
Views: 299
Thanks UncleVanya.

I still have a stock of litho film but no way to transfer digital files to it (no film writer). The shop that used to do it with azo film did a great job at 1000dpi and the azo was excellent media for this (high maxD and contrast) but I note that even azo products are disappearing not to mention equipment to write to them.

It's sad to see these hobbyist resources disappear as many younger folks have cut their teeth on such hobbies which have led them into technical careers. If we look 20 years ahead, it gives me wonder where we are going to find people with technical skills other than using a cell phone and texting. I understand technology marches on but the trend removes easy exposure to technical skills through hobbies and backyard experimenters out of the picture. Just my observations.

Anyway - anyone have a good resolution film writer - cheap and one that can do 5x7s?:)
Forum: Photographic Industry and Professionals 06-12-2018, 06:23 AM  
Looking for a Photo Service
Posted By Bob 256
Replies: 9
Views: 299
Maybe there is one of you out there who can help me with an issue not related to a Pentax product.

I do printed circuit work using photosensitized boards. These are copper clad boards with a thin photo-polymer coating which responds to light by polymerizing and retaining a pattern which protects copper beneath in a subsequent etching process which removed unprotected copper and produces the copper pattern for the finished product.

Previously, I've had a local service drop the pattern to an azo negative from a digital file for the master to expose the board (in a contact frame). About a year ago, this service went out of business so now I'm looking for someone who has that capability at a reasonable cost (typical cost was $15 for a 12" x12" azo). It has to be a fairly high resolution master (600 dpi or higher) and high contrast. Files are PSD.

Anyone know of a service like that who does mail-order work? I know they're hard to find because even high contrast film is disappearing from the market.

Thanks.
Forum: Photographic Technique 06-09-2018, 02:37 PM  
Astro Aperture requirements using astrotracer (milkyway photos)
Posted By Bob 256
Replies: 12
Views: 601
Absolute aperture (size) determines the brightness of point objects like individual stars. With wide angle lenses, this can be problematic because even with low f stops, the absolute aperture can be small. "Extended" objects like nebulae respond to the actual aperture (f2 versus f8), so they can be rendered brighter even with a wide angle lens while the stars might be considerably muted relative to the extended object. Hence, contrast between stars and nebulae will be controlled by the size of the aperture and the f stop, and that contrast will depend on the focal length of the lens (generally speaking). Large f stops don't necessarily mean bright stars but for nebulae and aurora they do what is expected of a "fast" lens and prov beneficial for shorter exposures.
Forum: Pentax SLR Lens Discussion 06-08-2018, 11:44 AM  
Lens Coverage - General Use
Posted By Bob 256
Replies: 19
Views: 591
The only thing I would recommend is an ultra-wide for landscape and some other shots you might want to take. It's hard to beat the perspective an ultra-wide has to offer for some applications. Note that the change in image perspective changes rapidly on that end so you would see quite a difference between your 35mm and a 28mm for example.
Forum: Pentax Camera and Field Accessories 06-07-2018, 07:40 AM  
More Pentax related 3D printable goodies
Posted By Bob 256
Replies: 28
Views: 1,156
Much Thanks - have been looking for a good 3D design program to go with my new printer - will try my hand at Fusion 360. Appreciate the tip and link.
Forum: Pentax Camera and Field Accessories 06-06-2018, 04:30 PM  
More Pentax related 3D printable goodies
Posted By Bob 256
Replies: 28
Views: 1,156
I found the Fusion 360 for students and faculty that is non-commercial but on Autodesk's site it appears to be a saleable software. Do you have a link to what you use? Thanks Arach101.
Forum: Pentax Camera and Field Accessories 06-06-2018, 06:24 AM  
More Pentax related 3D printable goodies
Posted By Bob 256
Replies: 28
Views: 1,156
Many thanks for your contributions Arach101! Some things for photography are pretty simple (I don't mean simple to 3D engineer) and 3D printing can be used to great benefit by those of us with access to a printer. Keep those designs coming.
Forum: Pentax DSLR Discussion 06-05-2018, 07:26 AM  
K-1 upgrade replaces sensor too?
Posted By Bob 256
Replies: 6
Views: 721
No better sensor exists at present (for the specific application in the K-1) and the cost of a new sensor would far exceed the refurbishment cost being charged (sensor cost is a considerable portion of the camera cost).
Forum: Pentax Film SLR Discussion 06-03-2018, 08:04 AM  
Can someone diagnose these light leaks in my Pentax ME?
Posted By Bob 256
Replies: 14
Views: 531
The appearance of these could also be of chemical origin and might be due to processing issues - maybe the fixing bath not completely doing its job or agitation was poor. On a couple of your strips, it looks like a line running the length of the strip, which could be an unusual light leak or a bead of chemical running the length when it's pulled out of the bath and hung vertically (a bit suspicious). See if there are milky looking areas on the negative where you see the "flashed" areas. If so, take one of the strips, manually placing it in a fixing bath (using fresh fixer) with good agitation to see if it will clear the areas that are coming out light in the print. If that's the case, all the shots can be saved by refixing & washing those negatives.

Just another thought.
Forum: Pentax K-70 06-01-2018, 02:44 PM  
HDR Modes
Posted By Bob 256
Replies: 8
Views: 476
If you have RT, you can pull out the center shot from the bracketed set (if you saved a DNG) and that can serve as a straight shot. Also, what bracket spacing did you use (Camera menu 3 >> HDR Capture). You can specify 1 or 2 stops. 2 stops usually provides better HDR effects depending on the range or tonal values in the subject. 1 stop can be a little flat sometimes.
Forum: General Photography 06-01-2018, 08:58 AM  
I'm just wondering about the guy who put this together
Posted By Bob 256
Replies: 7
Views: 753
About f22??
Forum: Pentax K-70 06-01-2018, 08:51 AM  
HDR Modes
Posted By Bob 256
Replies: 8
Views: 476
If you're talking about the K-1 versions, you should also have an HDR ADV mode. The AUTO is supposed to select the best mode for the occasion (from the types listed) but I use ADV the most. The best way to get a feel for the modes is to use them and see the results.

Note that the bracketed exposures for any of these are the same and are contained in the DNG file (assuming you are writing that to a card). The camera processes the HDR modes listed and generates a JPEG result (which is what you see on the LED display).

I have taken to processing HDR shots with a third party HDR program. I open the HDR DNG file in RAWTherapy, separate the bracketed images, and then process those in Photomatix which is the HDR processing program I use. Photomatix has a lot of control over the HDR effects - well beyond what you get with in-camera HDR. I use the ADV mode to get an idea of what the HDR image will look like (it approximates what I'm after better than the other modes), but that's about it. It's pretty convenient to press the shutter release and let the camera capture three shots in a single file, but sometimes more are needed, and then I go to bracketing mode - the downside of which is that a separate file is generated for each of the shots.

Bottom line is if you shoot in HDR and keep the DNG file, you can go back with an HDR program later and get what you want. If you only keep JPEGS, then the camera will do it for you and you're limited to those modes offered by the camera.
Forum: Pentax DSLR Discussion 05-30-2018, 07:50 PM  
Wifi Commander for Pentax is online (Windows app)
Posted By Bob 256
Replies: 58
Views: 3,270
I wondered why that Amazon drone dropped a cubicle in my front yard:D
Forum: General Photography 05-30-2018, 07:43 PM  
Fstoppers - "Lens compression doesn't exist"
Posted By Bob 256
Replies: 93
Views: 2,361
It's not the size of a nose but its extension relative to that. Consider two circles, the first 2 inches in diameter and the second 1 inch in diameter but let the second float 1 inch above the first. If you're a fair distance away, you'll see a 2:1 ratio (regardless of lens FL). As you move closer, the 1 inch circle will appear to grow faster than the 2 inch until from a distance of about 2 inches, they appear identical and the 1 inch covers the 2 inch. So, to answer swanlefitte's question, the fastest change takes place close to the subject and decreases exponentially as distance increases (it's actually a tangent curve).

Now if you adjusted lens focal length to keep the 2 inch circle a constant image size, the 1 inch circle would appear to slowly grow as you approached from a distance, and that would speed up as you got closer until it would be changing the fastest at the 2 inch distance (assuming 2 inches is the limit we put on this little mind experiment). Alternately, you could keep the 1 inch circle a constant image diameter, and the 2 inch circle would appear to shrink. To address your question, the tip of a person's nose changes size differently than the base which is the facial distortion seen.

Look up Hitchcock zoom. Alfred made use of this using early zoom lenses and a moving position of the camera to obtain a unique effect which has been copied since. I've even seen it done in digitally animated features. Really just "perspective distortion", but it really looks cool in a movie where the main element is kept constant size.
Forum: General Photography 05-28-2018, 06:28 PM  
Eye damage from the sun
Posted By Bob 256
Replies: 24
Views: 1,101
Good news. You might have had an allergic reaction to something - unusual for only one eye, but at least it wasn't your worst fear. Glad to hear you're good shape and wiser.
Forum: Pentax DSLR Discussion 05-28-2018, 03:17 PM  
Wifi Commander for Pentax is online (Windows app)
Posted By Bob 256
Replies: 58
Views: 3,270
Just a note for those of you wanting all those features - Andrea is doing this with time available and is to be commended on efforts so far. Some requests require a significant amount of developmental/debugging time so keep it reasonable (features that are worth the effort to others as well and features that are practical). Also, shoot a donation Andrea's way to make worth the time and effort, and to support those added features. This could really develop into a great Pentax tool but only if it's supported the right way by the Pentax community:)
Forum: Pentax DSLR Discussion 05-26-2018, 08:10 AM  
Understanding ISO
Posted By Bob 256
Replies: 22
Views: 1,177
It has to do with the sensor's capacity for handling light. You can think of each pixel as being a small bucket which gets filled up with water when it's exposed to light. Only so much water can be held in each bucket. The size of each of these little buckets is built into the sensor through its design and won't be changed thereafter unless a better design comes along. Ideally, you want to set an exposure so none of the little buckets gets overfilled by the brightest area in the scene. All the other buckets will contain less water which is completely ok. For good sensors, the amount of water in each bucket can be read out to extremely small values (let's say 1/64,000,000 of a full bucket), and any where in-between that and a full bucket. This determines how many shades of gray you can have (a lot, for a good sensor).

Now to increase ISO, you give the sensor less light, that means all the little buckets have less water in them in proportion to how much the exposure is decreased (let's say for this example that is 1/100 of a regular exposure). It's a simple matter when the water in each bucket is measured, its value is just multiplied by 100 to get a regular looking exposure. If you increased the sensor base ISO by 1000, just multiply by 1000 and so on........

Now if you have your head wrapped around this so far, we'll continue. First, there's a trade off in increasing ISO. Since there is less water in each bucket and we compensated by multiplying, the number of levels that can be measured decreases by that multiplication factor. In other words, the smallest value was 1/64,000,000 of a barrel originally, but if we gave the sensor 1/100 the amount of light, filling each bucket 1/100th of it original value, and multiplied by 100, the smallest value now becomes 1/640,000 of a barrel and we have fewer levels (fewer shades of gray) that can be captured. This contributes to a decreased dynamic range for the sensor, more noise (for reasons I won't get into) and at some point, really bad photos.

But to get back to your original question about lowering ISO - You can't go the other direction because of the sensor. If the sensor is exposed to more light (meaning the barrel content values would be divided), some barrels are going to overflow and the brighter portions of the image would be lost. The sensor just can't handle more light, period.

A camera manufacture could cheat and set the point where this overflow happens at a lower ISO value (say 10) but then by the time you get to usable ISO values, image degradation would have set in. It becomes a matter of putting the best sensor performance (where only the brightest image areas are near filling the pixel buckets) at a reasonable ISO value, and in fact, this is constrained since it has to correspond to the standard ISO definition. So if a standard exposure (at a given lens opening & shutter speed) produces a good exposure, a certain ISO must result.

Actually you can get your camera to a lower ISO than its lower ISO limit. Take the K-1 for example which has 100 as its lowest value. Set the camera to 100 ISO and put a 1 stop ND filter on the lens - the camera now has an ISO of 50. Forget about all else and for all practical purposes, you're shooting at an ISO of 50. The lens has to open 1 stop more or the shutter has to slow to half its former speed value (or you have to move the camera's ISO to 200 - which is actually only 100 now).

Increasing the capability of sensors probably won't do much for the lowest ISO value being lowered, but it will allow better performance at higher ISO values and allow those to be extended (or at least result in better images at those higher values).

As you can tell by this lengthy diatribe, I too have too much time on my hands, but I hope this helps your understanding of what's involved:)
Forum: Video and Pentax HDSLRs 05-25-2018, 07:07 PM  
video 101?
Posted By Bob 256
Replies: 10
Views: 413
The K-1 can record some beautiful video and make use of your stock of lenses, but it's not even close to the league of a real "video" camera in a good many ways. As mentioned, even some low cost "Video" cameras have features that the K-1 can't emulate (focus following, maintaining focus while zooming, to name just a couple). For uses like you mentioned, the K-1 is pretty adequate (most of your work will be in post production) but if you're into any involved video work, you need to look to a better type of camera more suited to professional video recording.
Forum: Pentax DSLR Discussion 05-25-2018, 07:43 AM  
Wifi Commander for Pentax is online (Windows app)
Posted By Bob 256
Replies: 58
Views: 3,270
Yes, Andrea. I'm running Windows 7 Pro on a Lenovo laptop E545 and it seems to be working fine. I was a bit antsy about the install (prior to doing it), but that went great and the only snag was a warning that my link wasn't functional once the app installed (I didn't have my K-1 or internet radio turned on), but once I got that up and rebooted your app, it was perfect.

I really like the ability to download files and the point and focus feature in liveview.

It's probably listed someplace, but what is the difference between the large and half size downloads? I did a test and the DNG file seemed to be a full sized one (which is what I usually want). Is the smaller sized file downsized in camera before it's sent or by the app after it has been received?

Thanks again for this great app!
Forum: Pentax K-1 05-25-2018, 07:30 AM  
Will it brick my K-1 if I apply K-1 Mark II firmware upgrade to it?
Posted By Bob 256
Replies: 21
Views: 1,332
The sad thing is that most likely, since the K-1II has come out, we won't see any more firmware updates for the K-1. I hope Ricoh proves me wrong, but that is the way with many other manufactures (and Ricoh would like to promote conversions of K-1s to K-1IIs).

I wouldn't take chances on using K-1II firmware on a K-1 (unless specifically endorsed by Ricoh) since that firmware may rely on hardware the K-1 doesn't have, and as said, the firmware probably has prohibitions preventing its use on other platforms. For all practical purposes, it's about like trying K-1 firmware on a K-3 (not quite, but technically the K-1II is a different camera than the K-1).
Search took 0.02 seconds | Showing results 1 to 25 of 300

 
Forum Jump


All times are GMT -7. The time now is 04:52 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top