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Forum: Pentax SLR Lens Discussion 12-27-2018, 04:10 PM  
Pentax-K 50mm F1.4 vs DA 50mm F1.8
Posted By DrMindbender
Replies: 26
Views: 1,430
I'm also considering going to one extreme and try for the "windows in the dark" look. So I'm curious to see how my new polarising filter can aid that by eliminating the reflected light off of the cars.

---------- Post added 12-27-18 at 04:22 PM ----------



Fair enough. Although, I should point out how long 2 seconds are during the dead of winter. ;)
Forum: Pentax SLR Lens Discussion 12-27-2018, 06:18 AM  
Pentax-K 50mm F1.4 vs DA 50mm F1.8
Posted By DrMindbender
Replies: 26
Views: 1,430
I know. I was just being snarky. However, the problem is that there is a semi-busy T intersection to the left of frame which results in annoying light painting of the scene with long exposures due to turning cars.

I really should see what my A 50mm/1.7 can do before I ask where I should throw my money around. The hoods and filters that came with it might achieve what I want better than a new lens. (Or fix the problem with A, F & FA lenses.)
Forum: Pentax SLR Lens Discussion 12-26-2018, 05:01 PM  
Pentax-K 50mm F1.4 vs DA 50mm F1.8
Posted By DrMindbender
Replies: 26
Views: 1,430
Well, daylight clear exteriors won't happen unless I would detonate nukes in orbit as the mother of all flashbulbs. ;)

However, what I'm trying to do is to produce a sharper image. Eliminating the graininess is out of the question since I'm fairly certain now that I can't drop the ISO to 1600 with any lens and I won't have the funds for a new body in the time frame I have. However, considering the high contrast of the subject matter, I was considering the possibility that the glass in the DA might make a difference by itself especially since I won't be using it fully open. I believe the term of the problem with my K that I've been describing is called coma with some general CA and fringing thrown in which may have been improved with modern coatings. If I was wrong about improvements to lens coatings, or vastly overestimated the improvement they would provide, I'd go with a DA 1.4 and possibly reconsider the A & F & FA 1.4's to get F1.6 & F1.8 that I can't get with my K 50mm/F1.4.


And I've been using a heavy tripod from the start with this type of shots.
Forum: Pentax SLR Lens Discussion 12-25-2018, 09:01 AM  
Pentax-K 50mm F1.4 vs DA 50mm F1.8
Posted By DrMindbender
Replies: 26
Views: 1,430
Indeed it will be an interesting and inexpensive experiment. :) It looks like it's comparable to the K 50/1.4 at F2, which is why I started musing about the DA 50/1.8, and it came with all the toys to push it to the limits. At the very least, I'll be able to decide if the A 50/1.4 and 1.2 are worth it before I go with a new body.

The big headache with depth of field is that I'm trying to freeze motion with photos like the one above so that I can bring out the interiors. Simply put, light streaks are boring. Unfortunately, the minimum shutter speed I need for photos like that is 1/125s which means wide open and high ISO. Add to that the train in the photo is switching to a daylight schedule in four months which is well before I planned to get a replacement body which forces me to decide if this is the best I can do now with what I have and with what lenses are available. :S
Forum: General Talk 12-24-2018, 09:07 PM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
An interesting little packaged which was delivered by Canada Post on a Sunday. I burned out the fungus (none internal) on the lens with hydrogen peroxide. However, I may need to use some ammonia to eliminate the "shadow" of the fungus on the glass.
Forum: Pentax SLR Lens Discussion 12-24-2018, 08:50 PM  
Pentax-K 50mm F1.4 vs DA 50mm F1.8
Posted By DrMindbender
Replies: 26
Views: 1,430
In my case, it's for night shots taken beyond 10 meters (infinity). So depth of field is less of a concern.


Basically, I'm looking to improve the quality of images like this:



In a perfect world, the lens I'm looking for would improve sharpness and allow me to open the lens wide enough to drop the ISO to 1600 from 3200 to reduce the graininess.While I doubt that the difference between 1.8 and 2 would be enough to drop the ISO, I'm ultimately hoping that 30+ years of improvements in lens making technology would make a difference with sharpness even if I'm still shooting at F2. But, ultimately, I know that there is the possibility that I won't do any better no matter how much money I throw at fast 50's and I'll need to move on to my next Pentax body.


In the short term, I'm going to see what the A 1.7 can pull off.
Forum: Pentax SLR Lens Discussion 12-24-2018, 02:23 PM  
Pentax-K 50mm F1.4 vs DA 50mm F1.8
Posted By DrMindbender
Replies: 26
Views: 1,430
So as the giftmas season starts to transition to the cold dark of winter, I'm starting to look at a supplement/replacement to my Pentax-K 50mm on my K5. The problem I have with it is that when shooting in low light conditions at F1.4, point light sources turn into horrendous blobs of light. As a result, I've been stuck at F2 or narrower. Now, my impression is that this was something that wasn't fixed with the M, A, F, & FA lenses and I'd prefer to avoid doing post work to fix it. As a result, and considering the cost of digital 50/55mm 1.4's, I'm looking at the DA 50mm F1.8.

The thing is though, I haven't seen a head-to-head comparison between the two lenses. So I'm not sure if the DA will be able to at least match my K at F2. So does anyone with experience with both lenses in low light conditions feel that the DA is an improvement over the K or should I hold out for a digital 50/55mm 1.4?
Forum: General Talk 12-03-2018, 07:33 PM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
I don't expect anything special or even good. However, the chance to play with an extremely long lens (1-4 meters!), no matter how slow or poor quality images, was too tempting to not gather all the adapter parts for it. That and I'm in it for less than $100 total.
Forum: General Talk 11-13-2018, 02:52 PM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
Well, if I had any doubts that Magnicons were rebranded Tokinas... (Finally got the SH-522 hood for it.)
Forum: General Talk 11-06-2018, 10:48 AM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
And that's #3 of 4.
Forum: General Talk 11-05-2018, 01:22 PM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
That's #2 of 4.
Forum: Troubleshooting and Beginner Help 10-31-2018, 01:44 PM  
Different mount models as a part source.
Posted By DrMindbender
Replies: 8
Views: 638
I should point out that my interest is nothing more advanced than KA lenses around the early 90's. So, aside from the differences in how each company implements camera aperture control, electronics shouldn't be much of an issue.
Forum: Troubleshooting and Beginner Help 10-30-2018, 08:28 PM  
Different mount models as a part source.
Posted By DrMindbender
Replies: 8
Views: 638
That's what worries me the most since it's possible that some lenses might have reverse threading on the front group even though they are also Sigma λII's.
Forum: General Talk 10-30-2018, 07:25 PM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
I wasn't talking about lenses in general. Just Sigma telescoping zoom KA lenses. ;)
Forum: Troubleshooting and Beginner Help 10-30-2018, 04:39 PM  
Different mount models as a part source.
Posted By DrMindbender
Replies: 8
Views: 638
In this case, I mostly need the front focus group (I'm not sure if it's fungus or the coating) and the mount screws. So those are the most needed if I have to junk everything else.
Forum: Troubleshooting and Beginner Help 10-30-2018, 03:20 PM  
Different mount models as a part source.
Posted By DrMindbender
Replies: 8
Views: 638
Since I decided to start playing the "as is" game on eBay, and I realized that my Sigma 75-300mm needs work, I began to wonder which lens mount versions would have the same components as the K-mount version with third party lenses? Basically, and it probably is easier said than done, if you were to replace the existing mount on a lens with a K-mount, it would more or less be identical to the k-mount version of that lens. The idea is that if I need parts, I don't have to wait for another k-mount version of that lens and I only have to worry about throwing out the mount components.


I have read that the Nikon AI/AI-S version of third party lenses might achieve what I want, but I want to be sure and to see what other options I have.
Forum: Troubleshooting and Beginner Help 10-30-2018, 05:56 AM  
Un-Macroing my telephoto lens.
Posted By DrMindbender
Replies: 12
Views: 716
Although, I do plan to get another one of the same model to restore this lens. So I may take a stab at seeing what would happen if I were to create the error I thought I originally did.
Forum: Post Your Photos! 10-30-2018, 05:42 AM  
Architecture Morning at City Hall
Posted By DrMindbender
Replies: 1
Views: 359
Basically the photo that convinced me that my Sigma lens was worth restoring to its full capabilities. (And to buy more from that era.)


Forum: General Talk 10-29-2018, 09:31 PM  
Your latest acquisition
Posted By DrMindbender
Replies: 15,684
Views: 1,051,880
And now I have purchased my third Sigma KA zoom. A 70-210mm to go with my 75-210 & 75-300. Good thing that there is only one more that I have any interest in or else I would have a problem.
Forum: Troubleshooting and Beginner Help 10-29-2018, 06:15 AM  
Un-Macroing my telephoto lens.
Posted By DrMindbender
Replies: 12
Views: 716
And just like that, this Sigma lens has caused me to add another thing to my accessory shopping list. :)
Forum: Troubleshooting and Beginner Help 10-28-2018, 06:39 PM  
Un-Macroing my telephoto lens.
Posted By DrMindbender
Replies: 12
Views: 716
And let this be a lesson to everyone: don't say that something is broken until you test it in your camera. Turns out that you can't determine if you reassembled your lens properly by merely looking through the barrel. It was only an optical illusion and I had put it back together correctly.

Unfortunately, I only found this out when I decided to see just how good this accidental macro was on the lens. :S
Forum: Troubleshooting and Beginner Help 10-28-2018, 08:41 AM  
Un-Macroing my telephoto lens.
Posted By DrMindbender
Replies: 12
Views: 716
It's possible since the middle group was lose and may have gotten reversed before reassembly. I never got to the point where I had removed individual lenses and only did a partial body disassembly.

It's also a telescoping zoom if that matters to those with experience.
Forum: Troubleshooting and Beginner Help 10-27-2018, 08:06 PM  
Un-Macroing my telephoto lens.
Posted By DrMindbender
Replies: 12
Views: 716
So after attempting to disassemble my Sigma λII 75-300mm and putting it back together again, it suddenly has turned into a very good Macro lens. While it does have interesting possibilities in this current state, that's not what I bought it for.

There were no leftover parts and I know that it has something to do with how the front elements are reassembled. However, I'm at a loss as to how to correct it. I am considering buying a second model as a parts source and I should be able to use it to solve the problem once I have it. However, I would like to figure out this problem before it would arrive.

Thoughts?
Forum: Troubleshooting and Beginner Help 10-25-2018, 07:17 PM  
Sigma λII MF 75-300mm f4.5-5.6 disassembly/cleaning.
Posted By DrMindbender
Replies: 2
Views: 400
Out of curiosity, aside from the mounts, are all Sigma λII 75-300mm f4.5-5.6 MF's basically the same? I'm thinking about getting a second one as a parts source. However, there are currently no cheap Pentax ones on eBay right now and I'm hopeful that the second one could create a single good lens.
Forum: Troubleshooting and Beginner Help 10-23-2018, 02:18 PM  
Sigma λII MF 75-300mm f4.5-5.6 disassembly/cleaning.
Posted By DrMindbender
Replies: 2
Views: 400
Well, my JIS set arrive today and I took a stab at disassembly.

The good news is that I have a better idea how this lens goes together.

The bad news is that I removed some of the lubricant and now the focus is stiffer.

The ugly news is that I have an idea why this lens was so cheap. It looks like either someone decided that tight was not enough when it was assembled or they had rusted shut over time. It was bad enough that I had to carefully bore out one of the screws and I gave up when three more showed signs of not budging. D:
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