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Forum: Visitors' Center 01-17-2015, 12:06 AM  
Crop Factor from a 645 to a K3 APS-C
Posted By promacjoe
Replies: 33
Views: 9,804
The only benefits you get from using a 645 lens on a K-3 or any 35mm camera, is flatness of field.

The focal length remains the same Regardless of what type lens you use. Only the image circle changes.

The usable portion of that image circle will be determined by the size of the film/sensor. Limiting your field of view.

Think of it like looking through a paper tube. a short paper tube, will give you one view. Double the length of the paper tube, And you will see less of the image. Magnification does not change only the field-of-view. However when printing, the relative image size will become apparent, and an increase magnification will be simulated. but only when printing on the same size paper. If you print them on paper relative to their sensor size, The subject would be the same size, but the larger sensor size will give you a larger field of view. you can achieve the same effect by cropping the larger sensor down to represent the aspect ratio of the smaller sensor. but you cannot go the other way.

It is a perceived magnification when printed on the same size paper.
Forum: Pentax SLR Lens Discussion 08-25-2015, 03:57 PM  
Preventing M42 adapter light leaks and dust ingress - an easy solution!
Posted By promacjoe
Replies: 40
Views: 14,458
try using a square cut O-ring. Being square cut, it will set flat against your camera mount.
Many automotive stores and pretty much all bearing supply houses can make up whatever diameter You need.
Forum: Photographic Industry and Professionals 05-19-2017, 10:09 PM  
Legal Advice for would be Professional Photographer.
Posted By promacjoe
Replies: 15
Views: 2,171
As I and many others have indicated, getting Legal advice over the Internet, may be a good starting point, but it is not something you should rely on. You may or may not get good advice off of the Internet. Someone who seems to be knowledgeable on the legal subject, may get you in trouble. Leaving you with a hefty fine or even jail time. Take everything you see on the Internet with a healthy dose of skepticism. You need to check it out from sources within your area. You mentioned two good sources, The photographic Association and a local attorney/barrister. just make sure the legal advice comes from someone who has experience in that Subject.

here in the US, there are thousands of websites that intentionally misrepresent history, legal advice, politics, current events as well as product information. For instance, If you believe all the doom and gloom articles about Pentax, Nikon, and Canon for example, you wouldn't buy a camera. Companies as well as other organizations/people have an agenda. They may just want to sell you a product. Others want to mislead you for some reason. Don't fall into that trap.
Forum: Pentax News and Rumors 04-24-2017, 10:12 PM  
We just have launched ...
Posted By promacjoe
Replies: 14
Views: 2,679
Last I heard, Cannon had a 50% drop in camera sales. And were supposed to jump ship for Cannon. Not me, even if Pentax does go belly up, I got too much invested in the Pentax gear. As long as my K3 holds out, or I can get a replacement, I am sticking with it. And even if I had to replace my gear, I would not go to Canon. I would probably go to Sony instead.
Forum: Troubleshooting and Beginner Help 04-02-2017, 09:39 PM  
Using UV filters for lens protection.
Posted By promacjoe
Replies: 42
Views: 3,101
As far as a lens caps goes, their great, and I use them whenever possible. But when I'm actively looking for wildlife, or shooting kids, sporting events or a air show, The lens cap goes in my pocket. The second or two that it takes to remove that cap, Can mean the difference between getting the shot that you want, or missing it entirely. And yes I use lens hoods as well. And so does my brother and his wife. But that did not stop that hundred dollar plus polarizer from getting damaged. But the $2000 plus lens was not damaged. Do I expect the filter to protect my lens from a catastrophic event such as a rock hitting it , No. And the lens hood will not protect it either. The lens hood can protect your camera, But in a different manner. It's like the bumper on your car and the windshield. They are both designed to help protect you. But they do it in different ways. the trick is, knowing when to use a filter, and knowing when not to use them. it's your equipment, you can use it however you wish. But I have 40+-year-old lenses that are in pristine condition, simply because I have tried my best to protect them. and I have taken a lot of pictures over the years.
Forum: Troubleshooting and Beginner Help 03-29-2017, 10:40 AM  
Using UV filters for lens protection.
Posted By promacjoe
Replies: 42
Views: 3,101
I acknowledge both sides of this argument. And I always keep protector filters in my bag. on one side people think that filters are only good for extreme damage. That's not what therefore. If something is going to hit your lens hard enough to break the filter, It would damage an unprotected lens as well. So to me that's kind of a stupid scenario. at least with a filter, your lens has a chance of surviving. But extreme damage like that is not why i keep a filter in my bag. It's for the common occurrences that show up on a regular basis while outshooting. The kids poking at your lens with there dirty hands, mud, chemical spray such as salt or the occasional drink that might be splashed on you. And the sand blowing on your lens, which can fog the glass, or at least the coating on the glass. Note: this may be a Long-term process. Every particle of sand that hits your lens can do a little bit more damage. It might not be noticeable at first, But over the years you may find more and more scratches in your lens coating. And when a sudden gust of wind comes up, the only thing you can do is point your camera downwind and hope for the best. my brother and his wife took a vacation to Yellowstone. While photographing the geyser, she got a little bit too close, and the hot spray from the geyser hit her fairly new Nikon 80–200 F2.8 lens. Fortunately they had a polarizer on it. The incident left a large permanent mark on the polarizer just off center. But the expensive camera lens was spared.

protector filters are good to have in your bag, you just need to know when to use them, And when not to.
Forum: Troubleshooting and Beginner Help 03-04-2017, 12:23 PM  
Do SD cards "wear out?"
Posted By promacjoe
Replies: 32
Views: 3,315
First of all, SD cards do have a limited read/write cycle. Although it is high they do give problems over time. And there is 1 moving part within a SD card , The right protects which. It is a physical switch. SD cards are extremely cheap compared to film. It is very economical to fill one to capacity, and then stored away. Depending on the camera, a 32 GB SD card can hold 800 to 1000 pictures, Your count may very significantly. You can compare the current cost of film and processing to the current price of one SD card. However, It is a very good idea to Backup your data. unfortunately any media that you use to back it up on, has a limited practical use value. Each storage device will get replaced eventually with a new medium, That requires new hardware. The older mediums may or may not be usable. You can call it designed obsolescent. By the time a SD card starts to lose its digital integrity, it may not be usable anyway due to this designed obsolescence. So it is a good idea to backup your data each time you change to a new type backup storage device.

Whether you use the card once and then retire it as a backup, or reformatted each time you use it is irrelevant. Always backup your data. And make sure you retire your old cards before they start giving trouble. Maybe keep count of how many times you reformat it, and retire it after so many reformats.

Just my thoughts.

Forum: Troubleshooting and Beginner Help 01-28-2017, 11:33 AM  
Pentax 70-200 not fitting on tripod
Posted By promacjoe
Replies: 8
Views: 1,193
For longer/heavier lenses, That is most any lens with a tripod attachment, you're better off with a gimbal head. Once properly balanced you can set it to any angle, without it trying to fall over. For longer lenses, even a cheap gimbal head will work better than a ball head.

Forum: Pentax Camera and Field Accessories 12-06-2016, 12:30 PM  
AA and AAA Rechargeable Battery Tester
Posted By promacjoe
Replies: 16
Views: 2,052
You cannot test a battery, using a multimeter alone. You must have a load in conjunction with the multimeter. All batteries have an internal resistance. This resistance increases as a battery is discharged. This resistance limits the available current as the battery is discharged. The higher this internal resistance is, the lower the available current. But the voltage will remain the same until you pull enough current out of the battery, then the voltage will drop considerably. For further explanation see this series of videos.

This guy is an electronics engineer and knows what he is talking about.

Forum: Pentax Camera and Field Accessories 10-11-2016, 05:56 PM  
Multiple filter size problem
Posted By promacjoe
Replies: 23
Views: 2,096
As others have posted, Get is good as you can afford. You can do a basic test of a circular polarizer if you have a tablet phone. Set the screen so it is displaying a white background, and place the polarizer filter in front of it. rotated 90° and see if there's any color change. Then flip it over and do the same thing. In the normal orientation, it should go from almost full brightness to almost full black. And there should be very little color change as you rotate it, if any. If you flip it over, there should be little if any change in the level of light. And this should not be any noticeable color change.

As far as protector filters goes, they are only meant to provides protection for dust, chemicals, fingerprints from kids, and light scratches. they will not protect from catastrophic events, such as dropping your camera, or rocks and other projectiles striking the front of your lens. If something of that type is going to hit your camera lens, there's not much you can do to protect it short of putting bullet proof glass in front of it. And to prevent you from dropping your camera, use a neck strap. And always inspect your gear before you go out.

A ND filter is a different subject, A good-quality ND filter is always preferable, but they can be expensive. My recommendations is to stay with the name brands. On all filters. Stay away from the chinese junk. In my opinion, Stay away from Vivitar. They used to have a few decent filters. But the last Vivitar filter I purchased, was advertised as all glass and high-quality, It turned out to be one glass filter, of poor quality and the others were plastic filters. I returned them immediately. you get what you pay for, and as far as filters goes, if you want good quality, you will have to pay for it.

Forum: Pentax Camera and Field Accessories 10-07-2016, 10:51 PM  
Multiple filter size problem
Posted By promacjoe
Replies: 23
Views: 2,096
the most needed filter is a polarizer. Next is a protector filter, Note, a protector filter should be used only when you feel it is necessary, otherwise leave it off. Neutral density filters are optional, You can use a cokin style filter holder for this one, one-size-fits-all. You can combine the two smallest and the two largest together, if you want to save money and use adapter rings for each. You may also need to purchase a lens hood to fit each size filter. it is good to note that filter size is less of a problem these days, when I started photography, you had to have dozens of filters. Black and white filters, tungsten filters, florescent filters, And the list goes on. At times I felt like I had to have a separate bag for my filters. I'm glad I do not need to do that anymore. Although I do carry to additional filters, a Tiffan 812 to warm up skin tones, and an enhancing filter for fall colors. Neither is necessary, both can be done in postprocessing. I just like to get as close to the image that I want without having to do a lot of postprocessing.

Forum: Troubleshooting and Beginner Help 06-19-2016, 10:00 AM  
Battery Charging.
Posted By promacjoe
Replies: 5
Views: 976
all batteries have an internal resistance that resist the flow of current. On a new battery, this resistance is low. On some batteries as they age, this resistance builds up and the available current is less than what the device needs to operate. Under normal conditions when the device is not drawing much power, the voltage can show that the battery is good. this is why you cannot use a voltmeter to check the condition of a battery. It needs to be under a load. Charge the battery, and make a note on how many shutter clicks you are able to get out of it. If it does not perform as expected, replace it. It's not worth the aggravation.
Forum: Pentax Film SLR Discussion 09-01-2015, 11:09 AM  
First development attempt...interesting failure
Posted By promacjoe
Replies: 31
Views: 3,440
I agree, Use that strip of film to practice loading your real. And inspected carefully. Also make sure you dislodge any air bubbles that can be trapped between the film. And good agitation is critical. Not agitating it properly can cause similar problems.
Forum: Pentax K-3 & K-3 II 08-06-2015, 01:31 PM  
K3 back LCD flickers
Posted By promacjoe
Replies: 7
Views: 1,186
I have the same set up as you have, and I am using it exactly as you described without any problems.

The only problem that I have had was every once in a while I would accidentally hit the battery grip switch, knocking it to the on position. This did cause a problem. So the first thing I do if I have a problem, is to make sure that switch is turned off. I only turn it on when I need to use it in portrait mode.

Make sure the grip switch is turned on only when you need it, otherwise turn it off.
Forum: Pentax SLR Lens Discussion 05-21-2015, 07:47 PM  
What would you choose, and why?
Posted By promacjoe
Replies: 25
Views: 2,323
just so you know, Not having autofocus on an 8 mm lens is kind of irrelevant. the focus range is so small and the depth of field is so great that you hardly have to focus at all. And since it's basically free, it would be a fun lens to have in your arsenal. don't reject it just because it's not autofocus.
Forum: Troubleshooting and Beginner Help 02-01-2015, 11:32 AM  
Can microscope damage DSLR matrix?
Posted By promacjoe
Replies: 9
Views: 1,688
I would recommend getting a way from on camera live view. Either use a separate monitor, or If your camera will work with it, a tethering cable, use it to connect to a tablet or laptop. this will reduce the heat produced by the camera. Unless you're using a really bright LED light, it should not hurt your camera. If you can look through the eyepiece without damaging your eyes, The camera will not be damaged. Also, try using polarized light to illuminate the subject. it can bring out details and colors that you may not expect. also a second polarized filter at the camera can isolate certain elements on wings and other surfaces that react to polarized light. You can simulate this effect by adjusting your LCD monitor to a solid white background and placing a clear plastic cup in front of it. Look at it through a polarized filter. Rotate the filter until the screen is dark. The cup will seem to glow. this happens because LCD monitors use polarized light. it is a very interesting affect.
Forum: General Photography 01-17-2015, 05:01 PM  
Out with a camera and often get heckled
Posted By promacjoe
Replies: 153
Views: 13,832
I've never had anything like that happen here. I live close to a major tourist town, and one thing that people around here don't want to do is mess with tourist. They bring in too much money. I've only heard of one incident when a tourist was being hassled by a police officer That was using a tripod. The tourist got a formal apology from the city, and the police officer got a formal education on the subject.

For me, the most that's ever happened is someone asked what I was shooting or if I was a professional. most people here are pretty tolerant of cameras. And won't hassle you.
Forum: General Photography 01-23-2015, 10:18 PM  
Out with a camera and often get heckled
Posted By promacjoe
Replies: 153
Views: 13,832
First of all never take legal advice from a police officer. They are not lawyers. besides that, They have a good reason why they don't want to mess with certain matters, It's called paperwork. they have to file a report on everything. so they will sometimes purposely and knowingly mislead you about the law. Trespassing is encroaching on anyone's property without permission, A sign is preferable. But if there's a fence with a latched gate, that is all that is necessary, And if the gate is locked, and they damage the fence to gain entry, It can be considered breaking and entering. At least in my state. even if there is not a fence, if you feel threatened by the intruder, or if you feel that the intruder is trying to vandalize your property in some way, they can be arrested for trespassing. Even if they have not done any damage.

As far as being harmed, You can be harmed physically or financially. Vandalism of property is considered harming someone financially.

I suggest you look up the laws in your state/country, and see how your laws are written. And don't take legal advice from police officers. Technically they're not supposed to give it. They are supposed to ticket or arrest individuals based on their understanding of the law, Then turn it over to the lawyers/Judge.
Forum: General Photography 01-20-2015, 11:21 PM  
5 Things We Need to Forget About as Photographers
Posted By promacjoe
Replies: 38
Views: 3,337
the fact that he starts off with the wrong information is a hint to his credibility. The first photograph was taken by Joseph Nicéphore Niépce in 1826 or 1827. Not 1725, He is only 100 years off, So it could have been a typo. But he needs to proofread his paper a little better.

And as much as I prefer not using a lot of bells and whistles in my photographs, we use the tools that work for each of us. Yes: we need to stop critiquing our equipment and learn how to use it properly. Yes: we need to stop relying on computers to make our photography better, and try to get it right from the start. but there are situations that computers can help us with. We just should not Rely on them to fix everything. Go out and take pictures. Pay attention and do the best job you can. When you need help from a computer use it. it's only a tool, and tools are made to be used.
Forum: Pentax SLR Lens Discussion 01-17-2015, 02:11 PM  
Lens identification help?
Posted By promacjoe
Replies: 7
Views: 1,513
remove the K mount adapter, Use the rear lens cap as a wrench, and look for a small pin on the flat part, underneath it. If it has the pin, make sure it is pressed all the way in. This is a locking mechanism for the Auto/manual switch.
Forum: Photographic Industry and Professionals 01-12-2015, 03:50 PM  
Man Arrested For Not Handing Over His Camera
Posted By promacjoe
Replies: 23
Views: 3,086
I have taken pictures of several traffic accidents that happened behind my house. Never once was I approach By any officer wanting to see my pictures or questioning my rights to take those pictures. I make sure that I never interfere with any investigation by staying well away from any formal accident scene.

He was arrested because he would not turn over his camera. Not because he would not allow the officer to view the pictures or even provide a copy of those pictures. the officer had no right to confiscate the camera, because the images on his camera was no more than what the officer could obtain for himself. They were not Direct evidence. nor could they be used in court as evidence directly. I believe he would have a lawsuit against the police officers, police department, and the city/County which they served. I would at least ask for a formal apology and all records of my arrest be sealed including mugshots and fingerprints. And all computer records be removed from any database. I would also ask for compensation for any time that I spent While under arrest, Along with any Money that I had to spend associated with this arrest.

as long as he was in his rights to take the pictures, and not interfering directly with any police investigation. This should not have happened.
Forum: Pentax SLR Lens Discussion 01-11-2015, 09:51 PM  
Let's talk lens filters
Posted By promacjoe
Replies: 38
Views: 4,373
ND filters and circular polarizers are somewhat of a must have. As far as protective filters, that is a personal choice you make. I have had situations when they were a absolute lens saver. For instance I have had kids poking at my lenses, soda and beer splashed on them. While on vacation in Yellowstone my sister-in-law got too close to a geyser, and the hot spray burnt the coating on her filter. But the $2200 Nikon lens she was using was spared. There has been other situations where if I forgot to take them off, I would have problems. I make a point to keep a protector filter in my bag. It's like having a spare tire in your car, hopefully you won't need it, but if you do, you have it.
Forum: Pentax SLR Lens Discussion 01-08-2015, 08:49 PM  
Front teleconverter quality vs rear
Posted By promacjoe
Replies: 10
Views: 3,054
A diopter filter increases the magnification of the lens. They are used for macro photography. but it does so at a cost. It reduces the focusing distance from the subject to the camera lens, so that it will no longer focus to infinity. It's like putting on reading glasses for your camera. A front mount tele-converter/tele-reducer also changes the focal length respectively, but it does so in a manner that maintains the range of focus of the lens. a diopter filter is about the same size as a standard filter. a front mount tele-converter is very large and very heavy, Normally much larger than the diameter of the original lens. Vivitar makes them as well as several other companies. they are not new, they were used in the early days of 35mm cameras without interchangeable lenses. And I'm sure other types of cameras use them as well.
Forum: Pentax SLR Lens Discussion 01-08-2015, 03:48 PM  
Front teleconverter quality vs rear
Posted By promacjoe
Replies: 10
Views: 3,054
Basically, I can only see two advantages to a front tele-converter.

1: you're not putting anything in between the electronics of the camera and lens.

2: there is a potential, depending on the lens used, to maintain the light capacity of the lens. But this is not guaranteed, hence the word potential. On certain lenses light capacity may decrease significantly if not more than a standard tele-converter.

Disadvantages include, but are not limited to,

1: as others have said, image quality may suffer greatly.

2: this is a heavy mass placed on the end of your lens. Any lens that rotates during autofocus can potentially have problems. this mass could damage the autofocus system within your lens/camera.

3: your autofocus may not even work with these lenses.

4: Even if the autofocus can handle the mass, that same mass can move the front element out of alignment with the other lenses and cause distortion.

5: SR will not see the new focal length. So SR should be turned off.

6: the metadata will not be correct. There is no way for the camera to ascertain the true focal length being used. Note: there is no guarantee that a standard tele-converter will compensate for the difference in focal length

For manual focus lenses however the front mount tele-converter can work, but some of the same problems will still exist. I do not recommend them.
Forum: Pentax SLR Lens Discussion 12-20-2014, 10:20 AM  
Infinity focus on various lenses
Posted By promacjoe
Replies: 11
Views: 2,309
Note: true infinity is a distance that cannot be reached, Nor can it be seen through a telescope.

As others have said, When it comes to infinity focus, no two lenses are the same. When doing astrophotography, you normally focus at the moon, If available, and everything else is said to be in good focus.
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