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Forum: Pentax DSLR Discussion 05-26-2022, 06:55 PM  
Are we really THAT rare?
Posted By BigDave
Replies: 6,847
Views: 930,049
Twie within the past month, at the NY Botanical Gardens, plenty of phones, many Canikons, I had the only Pentax. Rare breed we are indeed!
Forum: Troubleshooting and Beginner Help 05-17-2022, 08:08 AM  
What is "One Stop"?
Posted By BigDave
Replies: 68
Views: 3,262
Another thing to keep in mind, with memorizing f stops. Just remember two of them, f4 and f 5.6. Then you double every other one (or half going down) so f4, f5.6, f8 (double 4), f11.2 (the actual f stop, double 5.6), f16, f22.4 (rounded to 22), f32 and f45 (actually 44.8, rounded to 45). Going down from f4 gives f2.8 (half of 5.6), f2, f1.4 and then f1 (a very rare bird!).
Forum: Troubleshooting and Beginner Help 05-17-2022, 08:03 AM  
What is "One Stop"?
Posted By BigDave
Replies: 68
Views: 3,262
If you were to actually calculate the areas of the apertures of the different numbered stops (f8, f11, etc.) you would find out that the area from one "full stop" to the next is either 1/2 or double (f11 is 1/2 the area of an opening as f8, which is 1/2 the area of 5.6, etc.). This is all based on the focal length of a lens, so an f1 50mm lens would have an aperture opening of 50mm. Given that each one stop change means the opening has been cut in half or doubled, then that also means that the amount of light has also been cut in half or doubled. SO f8 lets in twice as much light as f11, etc.

f stops work in conjunction with the shutter speeds, which will also cut in half or double the amount of light at the standard shutter speeds (1/60/sec lets in about twice the light as 1/125/sec). ISO works the same way, with ISO 100 needing twice the light as ISO 200 to give the same exposure. The DIN system, common in Europe, uses log changes, so DIN 21 (ISO 100) needs twice the light as DIN 24 (ISO 200). 3 is a natural log change. Doubling or halving the light is a logarithmic change, so these systems all work nicely.

In review then, f11 @ 1/30 sec gives the same amount of light to the sensor/film as f8 @ 1/60 sec, and 1/15sec @ f16, and so on (all for a given ISO, say ISO 100). f11@ 1/30 sec at ISO 100 is the same exposure as f16 @ 1/30 sec at ISO 200 OR f11 @ 1/60 sec at ISO 200. Depth of field does not play into the exposure calculations, only the compositional preferences of the photographer.
Forum: Mini-Challenges, Games, and Photo Stories 03-01-2022, 08:45 AM  
Thematic Guns, Knives, and Ammo
Posted By BigDave
Replies: 94
Views: 5,583
WOW! 412 meters is like 450 yards! For a Rimfire that is LOOOONG! Even at 200 meters ( about 218 yards), that's about a 60 inch (5 foot) drop, About 36 foot drop at 450 yards! What were you aiming at, the moon??? Very challenging!
Forum: Mini-Challenges, Games, and Photo Stories 02-22-2022, 08:35 AM  
Thematic Guns, Knives, and Ammo
Posted By BigDave
Replies: 94
Views: 5,583
If they start asking what caliber it is, just say either 35mm or 200mm and see if you get a raised eye brow! Nice job on the conversion. You can't help if people are ignorant!

---------- Post added 02-22-22 at 10:36 AM ----------


The wood is in GREAT condition!
Forum: Mini-Challenges, Games, and Photo Stories 01-28-2022, 02:44 PM  
=planes, trains, boats and automobiles=
Posted By BigDave
Replies: 5,833
Views: 459,682
This is a late '90s or early 2000s Rav4. Still find them in the US, though now replaced by the newer bigger models.
Forum: Mini-Challenges, Games, and Photo Stories 01-15-2022, 08:15 AM  
Thematic Guns, Knives, and Ammo
Posted By BigDave
Replies: 94
Views: 5,583
Very nicely done! Now I know what to do with that old rifle stock I have!
Forum: Pentax K-1 & K-1 II 12-29-2021, 09:51 AM  
Pixel Shifted Images
Posted By BigDave
Replies: 1,601
Views: 212,287
Rondec, This is a great image, but a bit dark. Lighten it up a hit and you have a winner! Nice mood you captured!
Forum: Film SLRs and Compact Film Cameras 12-29-2021, 09:43 AM  
Gear P0rn - post it if you got it.
Posted By BigDave
Replies: 8,398
Views: 1,100,664
That voightlander is in pretty good shape!
Forum: Mini-Challenges, Games, and Photo Stories 11-17-2021, 10:19 AM  
Thematic Street Photography (No, Not THAT Street Photography) - Share Your Shots of the Roads
Posted By BigDave
Replies: 4,662
Views: 336,422
This will double in train photos too!W
Forum: Mini-Challenges, Games, and Photo Stories 11-17-2021, 10:07 AM  
Thematic Street photography
Posted By BigDave
Replies: 187
Views: 10,010
GREAT IMAGE Tokyo!
Forum: Monthly Photo Contests 07-07-2021, 10:58 AM  
Fremantle Maritime Museum
Posted By BigDave
Replies: 37
Views: 578
I would like to nominate this photo
Forum: Monthly Photo Contests 07-07-2021, 10:58 AM  
San Francisco Centre
Posted By BigDave
Replies: 25
Views: 387
I would like to nominate this photo
Forum: Monthly Photo Contests 07-07-2021, 10:56 AM  
Jim Creek Bridge, WA
Posted By BigDave
Replies: 24
Views: 451
I would like to nominate this photo
Forum: Monthly Photo Contests 07-07-2021, 10:55 AM  
Gateway Arch
Posted By BigDave
Replies: 22
Views: 401
I would like to nominate this photo
Forum: Weekly Photo Challenges 05-25-2021, 07:46 PM  
Caption Contest Caption contest - 25 May
Posted By BigDave
Replies: 14
Views: 796
Gravity SUCKS!
Forum: General Talk 05-14-2021, 12:07 PM  
The Joke Thread
Posted By BigDave
Replies: 4,932
Views: 426,055
For those members from the USA, If Pro is the opposite of Con, then what is the opposite of Progress? Please respond with your answer.
Forum: Mini-Challenges, Games, and Photo Stories 05-14-2021, 12:02 PM  
Thematic Street Photography (No, Not THAT Street Photography) - Share Your Shots of the Roads
Posted By BigDave
Replies: 4,662
Views: 336,422
Great light. Had you considered fill flash (the parked car)?
Forum: Pentax K-1 & K-1 II 05-14-2021, 11:40 AM  
Post your K-1 pictures!
Posted By BigDave
Replies: 34,338
Views: 3,390,558
Jerrylee- Nice images, but with these blossoms, you need to get the DoF up, so the aperture. F8 to 11 should do it. Great color!
Forum: Mini-Challenges, Games, and Photo Stories 05-14-2021, 11:35 AM  
Minimalism-Post your minimalist images here
Posted By BigDave
Replies: 2,484
Views: 250,928
AgentL, I like the darkness of this image. Nice contrasts too.
Forum: Weekly Photo Challenges 05-14-2021, 11:26 AM  
Weekly Challenge Caption Competition - 17th May
Posted By BigDave
Replies: 13
Views: 733
Like, I will get taller than the dog one day, right?
Forum: Pentax K-1 & K-1 II 05-12-2021, 12:38 PM  
Post your K-1 pictures!
Posted By BigDave
Replies: 34,338
Views: 3,390,558
Very nice image. I imagine the mist was from water being a bit warmer than the air!
Forum: Mini-Challenges, Games, and Photo Stories 05-10-2021, 08:03 PM  
Lets see Bridges
Posted By BigDave
Replies: 2,386
Views: 228,138
Why don't they bury the road and make an express from the Bronx or Queens right to JFK!? Hate going there!
Forum: Pentax Forums Giveaways 05-10-2021, 07:55 PM  
Pentax D FA* 50mm F1.4 Giveaway - Enter here once per day until May 18th
Posted By BigDave
Replies: 2,853
Views: 69,601
A late start, but maybe this is enough!
Forum: Pentax SLR Lens Discussion 05-10-2021, 07:54 PM  
prime, prime, everywhere a prime...
Posted By BigDave
Replies: 16,052
Views: 854,940
31mm Limited- starting to LOVE this lens!
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