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Forum: Pentax SLR Lens Discussion 11-27-2011, 01:46 PM  
Vivitar 28mm F2 aperture blades
Posted By chedoy
Replies: 38
Views: 25,063
Just an update. I took the lens apart, gripping it with two channel lock pliers per the pictures. It's right hand thread. Just as described. Twist the top half off and blades are exposed.

Cleaned the blades by closingthem to distribute the oil, wiping with a microfiber cloth with a little gasoline, repeating many times. Blades are snappy now.

This lens has always been way too soft wide open. I was hoping that was due to oil on the element under the diaphram blades. Looked like some there and I cleaned it. Nonetheless, initial tests inside indicate no improvement. Going outside.
.
Forum: Pentax SLR Lens Discussion 04-29-2011, 04:49 PM  
Vivitar 28mm F2 aperture blades
Posted By chedoy
Replies: 38
Views: 25,063
Thanks for the confirmation, Lowell!

What I did in the interim was to set the lens on top of my desktop PC, and the heat softened the oil so the iris worked (as long as the lens was warm). I can see that there is oil on the blades.

Since the front lens assembly appears to go back and forth as a unit, there is no alignment issue in reassembling it, right? If so, my goal is to just to limit the disassembly to that. Pentaxman said its tricky to get the helical threads aligned so I want to avoid that.

So if I can get my fingers on the blades, I'd try to clean them "in situ." A microfiber cloth dampened with solvent hopefully can draw off enough oil with enough applications.

Soldbear, I've read where some owners just dripped naptha thru the aperture arms. But I will try naptha. Alcohol, water, and oil don't mix.
Forum: Pentax SLR Lens Discussion 04-28-2011, 01:28 PM  
Vivitar 28mm F2 aperture blades
Posted By chedoy
Replies: 38
Views: 25,063
Hi to you disassembly experts. I have the Kiron/Vivitar 28mm f2. Its aperture blades are stuck. Earlier in this thread, pentaxman showed three versions. I have the middle one. Front element is stationary when focus ring is turned.

I've studied Paulo Gomes Flickr page where he takes the lens apart. I'm attaching his photo where he says that the front element screws off (with a firm twist) after other parts have been removed.

Then I saw Lowell Goudge's note that he just untwisted the lens (presumably the same construction) w/o the other disassembly.

Am I proceeding correctly if I do this? I've had the front cover off, so I could hold the lens by the two surfaces shown in the second attachment. And If I got the halves apart, I would just try to swab down the blades with solvent, rather than disassemble.

...or I could try to get my money back from the seller.
Forum: Pentax K-r 04-24-2011, 11:54 PM  
Cannot decide which color to get for K-r? Get them all!
Posted By chedoy
Replies: 6
Views: 2,633
Haha. I thought thems were real cameras.
Forum: Troubleshooting and Beginner Help 03-18-2011, 09:55 AM  
M42 Adapter stuck on M42 lenses
Posted By chedoy
Replies: 33
Views: 12,286
I bought a Bowen from B&H and also one off ebay, but they have always proved unwieldy for me. The are too hard to remove from the body, especially if changing lenses in the field. I did knock off some high points off both with a Dremel so they are easier to remove with the tool.

As for a flanged adapter from fotodiox, wasn't there a disclaimer that they cannot focus to infinity?
Forum: Pentax DSLR Discussion 10-30-2010, 08:20 AM  
Trigger Volt test - which is right ?
Posted By chedoy
Replies: 28
Views: 4,994
So you are saying that the meter does not read a voltage unless the flash has just been fired? In that case, the hot shoe voltage will not be anywhere near its maximum value.

A lot of digital meters read 1 when the measured voltage is higher than the range set on the meter. In line with it not being able to measure when the flash is charge up, that would be consistent with the voltage being way up there. My old SunPaks are over 200 volts, but designs differ,

As far as measuring .34 to 16 volts, I don't know why yours is so erratic, except I know that cheap meters load down the flash and make the voltage read far lower than its actual value.

Bottom line, if you're assuming your camera can tolerate 20 volts, Botzilla says 30-50 volts, and you're getting nonreproducible numbers, maybe hold off on using that sunpak.
Forum: Photographic Technique 01-13-2010, 10:12 AM  
Best photo advice
Posted By chedoy
Replies: 48
Views: 9,022
Get close.
Forum: Pentax DSLR Discussion 12-20-2009, 07:45 AM  
Poll: Which is BEST Low-Cost Pentax DSLR UNDER $300 Used?
Posted By chedoy
Replies: 51
Views: 22,309
Didn't see the K100D on the poll. Same photo specs as the K100D super except you don't get the early version (read - ineffective?) dust buster, and you don't have SDM power contacts?

Ditto for the K-M/K2000 being missing. Not that you could get one for $300, so I assume thats why it's not there.

The K10D is still a tank to me. Some people want huge cameras. I will trade off the pentaprism, higher MP, and other features for the size and better ISO.

I also think the S-R makes the later cameras more attractive than the earlier pentaprism models without it. I also consider age is important. Perhaps this is manufacter dependent. I have two almost ten year old Nikon P/S compacts that work fine, while two not as old Konica compacts are dead.
Forum: Pentax DSLR Discussion 12-17-2009, 02:04 PM  
K-x (white) kit for $$472.00 @ Amazon
Posted By chedoy
Replies: 47
Views: 9,244
Betcha I'm gonna be sorry I didn't pull the trigger, but I didn't like the resellerratings info on the vendor for the white K-X.

Anyway, there's next month.
Forum: Pentax DSLR Discussion 12-06-2009, 03:05 PM  
k100d bricked - Please advice!!
Posted By chedoy
Replies: 19
Views: 3,990
I ran my K100D on brand new Energizer lithiums out of the package for its firmware update.

Night as well call Pentax and get an estimate. Perhaps they can do it for a flat and (reasonable) fee.
Forum: Digital Processing, Software, and Printing 12-06-2009, 02:56 PM  
Problem Developing Tri-X 400
Posted By chedoy
Replies: 11
Views: 4,476
You loaded the film into a reel? What happened was that you didn't wind the film into the reel correctly and two or more layers contacted each other, preventing the chemicals from reaching the emulsion on one or more sides. I don't know what people use these days. When I did it, the reels were stainless steel and made out of thick rolled wire. You had to learn how it went in by feel.

I also did this on the first roll of 35mm film I ever developed. Still feel bad about it 44 years later as it was a friend's shots and I had started working in a photo lab and was supposed to know how to do this.
Forum: Digital Processing, Software, and Printing 11-12-2009, 11:59 PM  
digitalizing slides en masse?? buy, rent or build?
Posted By chedoy
Replies: 9
Views: 5,189
I've tried it several different ways. Ranked by my "IQ" rating.

1) Canoscan 2710 with a constantly crashing SCSI interface into a Win98 PC. Ran off 2300 slides at about a minute per scan. Most of them about 1800 pixels wide. Probably the best method. Wish I still had it. Took me three months to do 2300 slides.

2) Plustek 7200. USB scanner. $175. Supplied Silverfast SE software not too good for white balance/exposure. Most everything has to go thru Photoshop color cast removal. Did another 1500 slides/negatives. Most at 3000 pixels wide. About a minute per slide before PP. About the same as the Epson, worse if you figure the color issues.

3) Epson V500 flatbed. $150. 3-4 minute scans. Less color/WB issues. Comes with templates for 35mm. I had to guestimate a cardboard one for a few 120 slides and negatives I have.

4) DSLR with 70mm FOV lens on extension tubes. Also fooled around with a bellows and some M43 primes on my K100D.

5) Nikon CP950 @2MP digicam in macro mode. Simplest but a pain to refocus every shot.

If you build your own off a camera, a stable rig is nice so focus doesn't have to change. I found a slide holder on ebay for $15 and mounted it a bracket attached to the tripod socket. It came with a rail that gives me slide-to-lens adjustment, but I had to bend metal accurately to get the fixed vertical height. Also, the front has a bellows which comes out to cover the end of the lens Need to play around with the tubes and lenses for coverage yet. I suppose clothespins nailed to a board could work as a slide holder too.

If quality matters, get a more expensive scanner. Otherwise, the Epson, while slow, will do a reasonable job for snapshot type slides, as will your camera. And the camera rig, of course, is fast.

What I found, aside from the fact that my thousands of slides are tech junk, was an accumuation of dust that would require removal of the slide and washing in Edwal film cleaner. Didn't want to do that. There is digital ICE in the scanners, but it really increases the scan time.
Forum: Troubleshooting and Beginner Help 11-11-2009, 07:10 PM  
Pentax KX, but new to dslrs and lenses
Posted By chedoy
Replies: 16
Views: 9,322
For hobbyists, Pentax has the DA18-55mm and the DA50-200mm. The latter is $209 shipped from BHPphoto.com. Probably less at Amazon.com. It's a nice compact and light telephoto. It expands you zoom capabilty out to a decent range.

A bright 50mm prime is a nice lens to have in the bag, but that particular focal length doesn't fit my needs. Maybe a 35mm or 28 mm for me. In addition, looking at that auction jogged my memory because the seller says the lens will not fit a K20D. Some Ricoh lenses have an extra pin that will get the lens badly stuck on your camera. Of course, you can remove the pin. Google for info.

You can find another Pentax mount 50mm. Remember you give up autofocus, and focus can be very critical at the large aperture. Google for Depth of Field. Basically, with a large aperture (like F1.7) that part of the scene that is not in focus gets blurred. Used commonly as an artistic effect.
Forum: Troubleshooting and Beginner Help 11-10-2009, 11:58 AM  
Old flash on DSLRs
Posted By chedoy
Replies: 11
Views: 4,287
I wouldn't use a Vivitar 283 on a Pentax. Mine will put out 330 volts with fresh AA batteries on the hot shoe contacts.
Forum: Pentax DSLR Discussion 11-09-2009, 07:48 PM  
I'll try these batteries in my K-x
Posted By chedoy
Replies: 22
Views: 5,218
Yep. Why do 2000 maH Eneloops work when 2700 maH Energizers won't? Well, the maH rating is the capacity of the battery. 2700is more power than 2000 and would run a light bulb 35% longer, but the K-X camera shuts off when the voltage monitor falls below some set limit and we never get to use all that power.

Eneloops have a lower voltage drop, so the voltage monitor doesn't trigger and so you get to use more of its 2000 maH. Actually, I believe thay are only 1900 mah.

I like the OP's idea. IF Eneloops are still troublesome, why not the NiZn battery? Its voltage is nominally the same as Energizer lithiums.
Forum: Pentax DSLR Discussion 11-08-2009, 10:08 PM  
Help! New Pentax k-x owner...
Posted By chedoy
Replies: 7
Views: 5,103
Shoot, it's not hard to clean a sensor with a swab and the appropriate solution, but you must do it properly or you can destroy the camera. Here's a link.
http://www.cleaningdigitalcameras.com/


If that is too scary (and I agree that it can be a daunting task) doesn't Pentax market a sticky swab that you basically press onto the spot where the camera says there is dust?

Finally, if you use air, never use bottled air. It is guaranteed to spray liquid propellant onto the sensor. Use a bulb blower.

A camera shop should be stocking the products needed to clean sensors, or they should be offering it as a service. When I first bought a Pentax, I encountered big time dust after a week or two. Here's an example of when I first nopticed it. Those black dots are not birds. EXIF says f27.

I nominally clean about every other month, or when I notice a speck. If you normally use the maximum apertures, any resident dust usually won't even show up.
Forum: Pentax DSLR Discussion 11-08-2009, 09:35 PM  
K-x High ISO Test Shots :- )
Posted By chedoy
Replies: 9
Views: 5,401
Well, sometimes I sit in the cheap seats at indoor events with the DA 50-150mm at f5.6. That's when I am shooting at ISO3200 and 1/250 to stop motion blur with my K100D, coming back probably one stop under exposed, and with a big PP job with the RAW file to bring back levels and kill noise. Now I don't need to do that to put food on the table. It's just one of my photo interests.

Higher ISO capability allows us guys with slower lenses to get pictures that would have been impossible prior.

qquake2lL, That de-noised shot sure is sweet. I ran the first one thru noiseware with similar results. I'm convinced that I want a K-X now.
Forum: Troubleshooting and Beginner Help 11-05-2009, 04:25 PM  
Photo Editing Software
Posted By chedoy
Replies: 30
Views: 8,903
One thing I like about Adobe Photoshop ELements is how other software can integrate into it as a plug-in. I prefer to do input RAW images using the free Adobe Camera Raw for example. And I have the Noiseware plug-in, not free, but excellent.
Forum: Pentax DSLR Discussion 10-31-2009, 10:48 AM  
K-7 costs how much?
Posted By chedoy
Replies: 11
Views: 2,116
Some things go up. Others go down. After I retired, I have to cover my own health insurance til I get old enough for the federal program. My premium right now is $950/month, and it goes higher next year. Still, I am just glad I'm still covered, because my dependents rack up huge medical expenses.

I bet the K7 body dips under $949 here in the US before New Years.
Forum: Pentax DSLR Discussion 10-30-2009, 07:03 AM  
Got my K-x Yesterday, and it's Going Back to B&H Today - Known Battery Problem
Posted By chedoy
Replies: 24
Views: 4,566
So the Pentax Tech Center recommendation did not work?

As I understand it ..... Insert batteries. Wait 20-30 seconds before powering up camera, which allows internal circuitry to reboot and recognize battery type.
Forum: Troubleshooting and Beginner Help 10-30-2009, 06:49 AM  
K7 Noise at ISO800
Posted By chedoy
Replies: 19
Views: 4,689
Glad you have the settings straightened out. That's what I consider normal for ISO 800. The first shot you posted would have scared me off a K7 had I been interested.
Forum: Troubleshooting and Beginner Help 10-27-2009, 07:45 PM  
lost memory
Posted By chedoy
Replies: 10
Views: 4,136
The Pentax (and your regular Windows) format process doesn't erase the card. It just clears some headers that listed the file start address, and allows that space to be overwritten. I have tested and can recover all the pictures after a format.

Find a friend with a Canon camera. The Canon's have a low level format option that will fully wipe out the picture files, and the above programs won't be able to recover anything. Really easy and fast, as long as you both use SD cards.

There are utilities like Eraser from Sourceforge. It is designed to make multiple pass writes of data patterns to hard drives and is good enough to foil CSI type forensics experts. If set up to just make one pass, that's good enough to scrub files off a drive that you want to give away. You can run it on a drive and it will scrub all currently un-used space too. It will also work on card reader contents. It takes some tech skill to install and set up. After that, "erase" become one of the options like "copy", "delete". etc when you right click on a file. Like anything else with such capabilities, one could probably screw up with it and crash a Windows install. Just wanted to point out such tools are available, and the sourceforge people seem pretty reputable.
Forum: Troubleshooting and Beginner Help 10-26-2009, 07:10 AM  
lost memory
Posted By chedoy
Replies: 10
Views: 4,136
Three FREE programs that can recover deleted pictures. I've used all three. The last one has been able to recover images from a corrupted card that the first two couldn't see. First two are easier to use. in my opinion. I've run the last two on VIsta.

Recuva
Recuva - Undelete, Unerase, File and Disk Recovery - Free Download

PC Inspector Smart Recovery
CONVAR & PCinspector Data Recovery Datenrettung recupero dati datarecovery rcupration donnes

Zero Assumption Recovery (free if you only use for image recovery)
ZAR data recovery software - do it yourself data recovery and digital image recovery.
Forum: Troubleshooting and Beginner Help 10-24-2009, 10:19 AM  
K7 Noise at ISO800
Posted By chedoy
Replies: 19
Views: 4,689
Wow, I'm dismayed, but maybe it's the settings and exposure. I don't own a K-7, but I would look at the NR settings. If you're going to shoot in JPG, you probably want to have some in--camera NR turned on. How much is up to you.

This is based on what I do for my Olympus E510, which s a very noisy sucker. Turn the in-camera NR up higher for JPG shots. I assume it's not off right now? Or turn it off for higher ISO shooting and post process it out. Also, under-exposure really aggravates noise.

Most of the time, mild noise doesn't print anyway, and is not noticeable in a screen shot.

Here's a 100x crop from your flikr image, right side run thru Adobe Elements with Noiseware plug-in. It's not all that sharp on either side, being a hazy shot anyway.
Forum: Troubleshooting and Beginner Help 10-24-2009, 09:38 AM  
50mm - what's the appeal?
Posted By chedoy
Replies: 51
Views: 6,434
No appeal here. For me, the crop factor relegates my manual 50mm to the shelf. I would rather use my Tamron 28mm as a small lens.

I think the 50mm's are popular and have staying power because they give you a inexpensive, good IQ, and fast prime since they were originally designed to be the lenses sold with film bodies. No longer inexpensive for Pentax, it appears.

I am surprised that the Pentax 50mm AF has gone up to $360. When I first bought a K100D back in 2006, I recall they were going for around $200-250. But maybe my memory is bad.
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