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Forum: Pentax SLR Lens Discussion 5 Days Ago  
Aperture diffraction question
Posted By rgknief60
Replies: 10
Views: 570
There are diffraction calculators that tell you when diffraction begins for a given sensor, and give you a starting point. If memory serves, diffraction begins for my K-1 at about f5.6.

That said, the optical formula of a lens may not be the sharpest at f5.6, and I might see better performance for example, at f8, even though diffraction has begun. Practically speaking, while I may see the difference between f5.6 and f8 in regards to the depth of field, I don't know that I can see the difference in diffraction. Most of the time there is no need to worry about the absolute sharpness for a given lens/sensor combination unless you are dealing with high magnification focus stacking.
Forum: Visitors' Center 6 Days Ago  
Pentax Image Transmitter 2 software
Posted By rgknief60
Replies: 2
Views: 214
The software sometimes comes up in the marketplace used. You can also post in the wanted section of the marketplace.
Forum: Mini-Challenges, Games, and Photo Stories 03-04-2024, 09:30 PM  
Thematic Show your texture, pattern, repetition, shape etc. shots here!
Posted By rgknief60
Replies: 4,173
Views: 323,226
First Flower Image(s) of 2024. 85 image stack in B&W to emphasize texture. Crop.
Forum: Mini-Challenges, Games, and Photo Stories 03-03-2024, 04:48 PM  
Thematic Bigger Flowers
Posted By rgknief60
Replies: 4,333
Views: 262,452
First flower image of 2024. This bloom was not open this morning, almost there now. Eighty-five image stack, Laowa 100mm macro & K - 1.


Amaryllis Detail
Forum: Pentax SLR Lens Discussion 02-19-2024, 06:48 PM  
Pentax 300mm/f4.0 A* with 1.4x TC on K20D - focusing
Posted By rgknief60
Replies: 22
Views: 1,023
Nice images.


I used the K20D and the 300mm A* for quite some time. I still own, but rarely use them. I also used teleconverters with them, mostly with a tripod. The 300mm A*, while not super expensive, was not a bargain lens when I got mine used. It was the best I could afford at the time.

I think that you do amazingly well with the combination. I'm not sure that I could handhold and do as well as you. I start to have issues with noise at ISO 800 as well.

The good news is that noise reduction software is much better than it used to be. Raw Therapee does a good job. It has a learning curve. Forum member The Squirrel Mafia has a Raw Therapee Thread with links to download the latest version--and it is free! I have not tried it with the K20D, but the program may allow you to boost the ISO a bit. As noted above, if you shoot raw, you are able to recover more detail and keep a bit more dynamic range. You do need to process the raw image to get the benefits. Raw Therapee is a good raw processor. Hopefully you also received the CD for the K20D which has the Pentax utility for raw processing as well. PM me if you did not.

One issue I have with the 300mm A* is its long minimum focus distance. A few years back I actually had to back up to get a hummingbird in focus, and ended up with a very tiny image in the center of my frame. To counter this issue I use an extension tube to shorten the MFD. The drawback is, of course, less light, but you do shorten the focus distance and increase magnification. As with a teleconverter, increasing the shutter speed helps.

As noted above, the ultimate solution for your problem is a body with better noise performance. Check out the reviews for the bodies mentioned, look at some of the others, and watch the marketplace. Once you've managed to save up a bit, you wil find a nice body you can afford.

If you have any other questions about the K20D, I'll try and rack my brain to answer, or take it out of storage and play with it again! :) More likely, someone else will chime in with an answer quickly before me.

EDIT: one last thing. My copy of the 300mm A* has never produced images as sharp as the DA* 300mm F4. I have resolved a lighthouse's fresnel lens with a 2x teleconverter well enough to see the steps on the lens at a half mile away. Your mileage may vary.


Roger

Five image panoramic taken with the K20D 300mm A*, Pentax K helicoid extension tube, and tripod. We were not allowed to go off trail. This subject was OOF without the extension tube. Actual image 8300 pixels wide.



Panoramic at the Ridges
Forum: General Photography 01-11-2024, 09:11 PM  
Your Flickr 2023 year...
Posted By rgknief60
Replies: 30
Views: 1,341
For an account not searchable...or so I thought, I was pretty surprised. I mainly use Flickr for posting here on the Forum.
Forum: Mini-Challenges, Games, and Photo Stories 10-28-2023, 08:46 AM  
Thematic Show your texture, pattern, repetition, shape etc. shots here!
Posted By rgknief60
Replies: 4,173
Views: 323,226
I liked the textures so I did a Pixel Shift Focus Stack using macro rail. Second image is actual pixel crop at 1024x1024. Xpost.

I did not know it until reviewing some of the images, but this log was crawling with activity, even in the cold weather. With the exception of a tiny fly, the exposure was too long and/or the subjects too tiny to resolve as more than tiny spots. My guess is spring tails.



Orange Fungii


Orange Fungus - actual pixel at 1024x
Forum: Lens Clubs 10-28-2023, 08:35 AM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
Pixel Shift Focus Stack using macro rail. Did not expect to find anything with color except leaves on the trip to Door County, so was surprised with this find. K - 1 & FA* 200mm F4 @ f16. Exposure time was .3 sec when I started, and 1.3 sec at end of stack, so a bit over 5 seconds for entire pixel shift files at the end. There are a few screen door artifacts from light change during the five second exposures that don't show here, but I can clean up if I want to go bigger. Second image is actual pixel crop at 1024x1024. Xpost.

Sometimes it is hard to know what step size to use "in the wild." I tend to miss areas in focus, so I try to overlap a bit. I took another stack using just the focus ring using Liveview, and the result was fine at about 10 images, vs the 90 I did with the macro rail. So I spent about 10-15 minutes longer on the subject than was necessary!

I did not know it until reviewing some of the images, but this log was crawling with activity, even in the cool weather. With the exception of a tiny fly, the exposure was too long and/or the subjects too tiny to resolve as more than tiny spots. My guess is spring tails.



Orange Fungii


Orange Fungus - actual pixels at 1024x
Forum: Pentax K-1 & K-1 II 10-25-2023, 07:00 AM  
Pixel Shifted Images
Posted By rgknief60
Replies: 1,738
Views: 237,260
Thanks!
Forum: Pentax K-1 & K-1 II 10-24-2023, 09:11 AM  
Pixel Shifted Images
Posted By rgknief60
Replies: 1,738
Views: 237,260
Pixel Shift Focus Stack using macro rail. Did not expect to find anything with color except leaves on the trip to Door County, so was surprised with this find. K - 1 & FA* 200mm F4 @ f16. Exposure time was .3 sec when I started, and 1.3 sec at end of stack, so a bit over 5 seconds for entire pixel shift files at the end. There are a few screen door artifacts from light change during the five second exposures that don't show here, but I can clean up if I want to go bigger. Second image is actual pixel crop at 1024x1024.



Orange Fungii


Orange Fungus - actual pixels at 1024x
Forum: Mini-Challenges, Games, and Photo Stories 10-24-2023, 07:33 AM  
Thematic Insects
Posted By rgknief60
Replies: 1,437
Views: 79,201
Surprised to see these out and about. This individual was safely ensconced in the seedpuff, but came out to look around when we held the stem still for taking pictures. All images are somewhat soft as the wind never died down. First image is a two image stack. My sister either held the stem still, or held the diffuser. Definitely a two person shot. Xpost.


Ladybug's Home


Ladybug
Forum: Lens Clubs 10-24-2023, 07:30 AM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
Surprised to see these out and about. This individual was safely ensconced in the seedpuff, but came out to look around when we held the stem still for taking pictures. All images were somewhat soft as the wind never died down. First image is a two image stack.


Ladybug's Home


Ladybug
Forum: Lens Clubs 10-20-2023, 09:34 PM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
Today's outing with the macro lens. I sort of liked the effect of the wind's painting with the leaves & trees, so I kept the stack.


Painted by the Wind


A Splash of Color
Forum: Lens Clubs 10-16-2023, 06:54 AM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
Thanks. I suspected it before my last eye appointment, as the lights had bigger halos around them.




Appreciate the help. The trees are just starting to change and the colors seem muted to me. That is normal some years, especially years during which we experience drought. Is it real, or is it cataracts? :)
Forum: Lens Clubs 10-14-2023, 10:48 AM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
From this summer's trip to Door County, WI. K-1 handheld six image stack cropped to 11.6MP. Handheld stacks at 200mm are always a bit dicey for me, this turned out better than most.

I just found out that I possess "baby" cataracts. Practically speaking, as they progress to the point where they need to be removed, my vision, especially the color end of things will change. The amount of change varies from person to person.

I tend to add a contrast and saturation in my images while trying to keep from going too far. If it appears that some of my images are way over processed, could you kindly let me know? I'd sure appreciate it. Thanks! :)
Forum: Pentax SLR Lens Discussion 10-11-2023, 04:28 PM  
ZhongYi Mitakon APO 200mm F4 MACRO Aperture Priority exposure problem
Posted By rgknief60
Replies: 10
Views: 836
This is the only listing I found when I searched for the lens after @JPT made us aware it is available. At that time two were available. Now there is one. Might have been a test to see how quickly they would sell in K-mount.




Thanks for the images. What is the subjct that you shared?

Glad to hear it is a sharp lens. Is the link above where you got yours? How do you like the working distance? Please write a review for the Lens Review section, and share some images in the Macro Thread. Thanks!
Forum: Pentax News and Rumors 10-09-2023, 12:08 PM  
New patent of nano-level antireflection structure composite optical element
Posted By rgknief60
Replies: 13
Views: 2,078
For some reason trilobite optics come to mind. Need to go back and research that again.
Forum: Lens Clubs 09-29-2023, 11:22 PM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
Thanks for the info on cross polarized lighting with flash. I was unaware of it, and will look into using the technique. Sort of went down a rabbit hole reading about it.



Thanks for the stacks. Good job.



Again, nice stacks. I only have version 1.x of Affinity, and its stacking, while okay, was not quite ready for prime time. It looks like version 2.0 is an improvement.

Like the colors, and the depth of field! You must have been a ways back.



These bring back favorite childhood memories of times when they used to almost cover the sidewalks and roads. I don't recall the last time I saw one, must be a couple years, at least.


That's one fine rose.


Don't get to see much of the K10D and its fine colors. Shows once again that you don't have to have high megapixel counts for fine images. Thanks for posting.
Forum: Welcomes and Introductions 09-26-2023, 03:40 PM  
Hello from Poland
Posted By rgknief60
Replies: 10
Views: 322
Welcome from Illinois, Marek! I look forward to your images, especially with the M42 lenses.
Forum: Lens Sample Photo Archive 09-24-2023, 02:32 PM  
SMC Pentax-FA* 200mm F4 Macro ED [IF]
Posted By rgknief60
Replies: 20
Views: 5,021
One of my favorite subjects. This summer for some reason, they are skittish, and i've not had time to get them habituated to me.



Male Ruby Throated Hummingbird
Forum: Photographic Technique 09-22-2023, 08:55 PM  
Not another equivalence discussion... Please help me understand acceptable sharpness
Posted By rgknief60
Replies: 7
Views: 931
I've got lots of images that are quite sharp--if you view them on the web. I'm happy with them. I would not print and hang them on the wall. Some of the images I saved from years ago are now "acceptably sharp" due to AI. A few I could probably print.

Here is an example of how AI changes what is acceptably sharp for me. The first image is OOC. The second is processing with Denoise AI. The last image is after using Sharpen AI.


Topaz AI's Comparison with Original JPG
Forum: Pentax K-3 III Monochrome 09-19-2023, 07:40 PM  
It's shipped! Advice on cards, spare batteries and such?
Posted By rgknief60
Replies: 14
Views: 824
Since the slots run at different speeds, it is not worth getting a real fast card for the UHS-1 slot unless you want the download speed.

This is probably apples and oranges since I don't have the mono version. Since I could not find out the rate at which my color K33 exports video, I got the fastest card I could afford that was on sale at B&H. It is a Sandisk Extreme Pro 300MB/s V90 UHS-II 64GB card. I have my video set to use that card in slot 1, of course.

I was recording waiting for mama eagle to return to the nest, and the video kept shutting off on me. Couldn't figure out why. When I got home, I found that 4K video records for 7:21 then stops at 3.98GB. I keep a Sandisk 256GB UHS-1 micro card in slot 2. I've also used a Lexar 1066x V30 256GB micro card in slot 2 with no issues.

The 300MB/s Sandisk is one of the few full size cards I have. I've almost exclusively used the 265 & 512 sandisk micro sd in the K-1 & K33 with no issues. For some reason, they are less expensive. A 128GB Lexar I gave my sister all the sudden showed no files and would not record in the first slot on the K3 II. It is possible the card was improperly removed from the computer, and the file system got corrupted. That has not happened to me before. But I am a bit wary of the card since I don't know if it was user error or a card issue. It works again after a in-camera format.

When you record using your mono K33, could you let us know how long you can record at 4K before you hit the 4GB barrier? It may be you don't need a card as fast as the color version of the K33. It would be an interesting comparison. Thanks!

Roger
Forum: Welcomes and Introductions 09-19-2023, 06:23 PM  
Hello from Japan.
Posted By rgknief60
Replies: 13
Views: 260
Welcome from Illinois. Thanks for posting your image.
Forum: Visitors' Center 09-14-2023, 04:51 PM  
software for k-5
Posted By rgknief60
Replies: 8
Views: 903
Good suggestions above.


Free stuff: I use Faststone image viewer for quick post processing. It does 90-95% of what I usually do with my images. Raw Therapee is a great free program with a lot more features I use it primarily for pixel shift. It has a learning curve. The Squirrel Mafia has a thread here on the forum for it. Gimp has good reviews, but I've not used it. It has a learning curve. Irfanview & XnView are also free and on the net for years. There are some non-Pentax image formats I can only read with XnView.

Paid stuff:

I use Photoshop CS6 extended (old!) for advanced stuff that Faststone does not handle as it was a one time purchase. Now you have to rent the software. It is the "industry standard" with a strong learning curve, but there are lots of resources to help. Affinity has a lot of features for the price.

I use Zerene stacker for focus stacking. It has the best edit tools for stacking. Helicon Focus is another stacking utility. It is faster than Zerene, but the editing tools are not as advanced. Both are expensive.

Topaz Labs has lots of great little plug-in & standalone utiltites. Sometimes the AI versions of denoise, sharpen, and detail do amazing things.

DaVinci Resolve has a free version for editing video. It does most things non-professionals need. It will take a while to learn.

Any specific needs, just ask. We have a lot of folks who can help!
Forum: Lens Clubs 09-12-2023, 02:42 PM  
*Macro* lens club
Posted By rgknief60
Replies: 5,102
Views: 682,690
Thanks for all the info, and the additional beautiful images. I'm not by nature an early riser, but knowing their pattern will probably be enough to roll me out of bed next year! :) My sister a couple blocks away caught one on her Iphone a few weeks back, so I know that they are in the area.
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