Forgot Password
Pentax Camera Forums Home
 
Log in or register to remove ads.

Showing results 1 to 12 of 12 Search:
Forum: Pentax SLR Lens Discussion 10-04-2015, 03:38 PM  
Lens mechanics question: Aperture vs focal length
Posted By joseph_me
Replies: 7
Views: 1,257
I was thinking about this for a while: let's say I have a manual lens, 70-300mm f/4-5.6. That means at 70mm the max aperture is f/4, and at 300mm the max aperture is f/5.6 (Right?).

What would happen to the lens, the body, or IQ if I manually set the lens at 300mm and aperture ring at f/4? Would the camera explode or the lens spontaneously combust? (kidding!)

I took some pictures and compared it but could not see much difference - though that might be due to my untrained eyes.

I also looked it up online and read an article that said it could damage the mechanism for the aperture because it will try to open beyond what the focal length allows.

What do you think?
Forum: Troubleshooting and Beginner Help 10-04-2015, 03:17 PM  
Teleconverter for sigma 70-300mm to k100d
Posted By joseph_me
Replies: 12
Views: 1,358
Ahh I see, everything now makes sense. Thanks everyone for your help. I'll post some pictures of the moon if I get a clear night tonight :D
Forum: Troubleshooting and Beginner Help 10-04-2015, 02:17 PM  
Teleconverter for sigma 70-300mm to k100d
Posted By joseph_me
Replies: 12
Views: 1,358
Thanks boriscleto and jatrax for your help! I think I have an idea as to what I need to do.

That raises another question though: the 2x TC will cost me 2 stops, so f/4-5.6 becomes f/8-11? Does that actually change the way the aperture ring moves or is it just blocking some light?

Sorry for the dumb questions, and thanks for your insight!
Forum: Troubleshooting and Beginner Help 10-04-2015, 02:04 PM  
Teleconverter for sigma 70-300mm to k100d
Posted By joseph_me
Replies: 12
Views: 1,358
It does have an aperture ring. I think when I set it to A the camera will adjust it electronically with the dial, or otherwise I could use the ring itself. I'll have to use the ring to set it with the teleconverter. Does that change the way I need to mount it?
Forum: Troubleshooting and Beginner Help 10-04-2015, 01:41 PM  
Teleconverter for sigma 70-300mm to k100d
Posted By joseph_me
Replies: 12
Views: 1,358
I've recently bought a Tamron MC 2x Teleconverter for my K100D ($15 - I hope I wasn't ripped off), and I want to use it to take pictures of the moon and some wildlife. I have a Sigma DG 70-300mm that I'd like to use with the teleconverter.

Now the problem is that I don't really know how the teleconverter will work with the lens. Will I have to mount it to the lens first? To the body first? Does the aperture setting matter when I'm mounting it? It doesn't have an actual ring, just the setting for adjusting electronically.

I do know that there are no electronic components to the teleconverter, so I'll have to focus and set the aperture manually. But is that all I need to know?

Any help is greatly appreciated! Hopefully I can get those moon pictures where I can actually see some craters!

Joseph
Forum: Welcomes and Introductions 09-11-2015, 07:35 PM  
Hello from an excited newbie
Posted By joseph_me
Replies: 15
Views: 1,320
I have two pictures that I really like. Anything you notice that could've improved the shot: please let me know! I'd love some constructive criticism.
Forum: Pentax SLR Lens Discussion 09-11-2015, 06:54 PM  
18-55mm 1:3.5 VS 28mm 1:3.5 (Is there a difference?)
Posted By joseph_me
Replies: 17
Views: 2,528
What lens would you take if you had to take only one lens to a 2 week long trip to Europe? And why?
Forum: Pentax SLR Lens Discussion 09-11-2015, 06:32 PM  
18-55mm 1:3.5 VS 28mm 1:3.5 (Is there a difference?)
Posted By joseph_me
Replies: 17
Views: 2,528
Hi Everyone,

You guys are so awesome, thanks for all your feedback. I guess one thing I've learned is that I just have to try them both: seems like they both have their pros and cons.
Tomorrow I'm going to a dinner party, and I think I'll likely take the kit lens (it has auto focus: I don't want to make people pose for five awkward minutes while I fumble with the focus ring haha).

And by the way:


Sliver Surfer: Are you a camera god? :o
Forum: Welcomes and Introductions 09-11-2015, 06:23 PM  
Hello from an excited newbie
Posted By joseph_me
Replies: 15
Views: 1,320
Hi everyone,

WOW, thank you so much for all your replies - you guys are so welcoming and I feel right at home.
We had a really old windows 95 computer, and it never occurred to me to try to recover the hard drive. Now I know to back up everything I take!

I have a k100D: love it to death. Currently I'm using SMC Pentax-M 50mm f/1.7 with it. As of now I'm basically taking anything and everything I see, but I like shooting flowers and symmetrical stuff. I'll post pictures when I take some post-worthy stuff.
Forum: Pentax SLR Lens Discussion 09-09-2015, 07:53 PM  
18-55mm 1:3.5 VS 28mm 1:3.5 (Is there a difference?)
Posted By joseph_me
Replies: 17
Views: 2,528
Hi jatrax,

Thanks for your response!

The kit lens I have is SMC Pentax DA 1:3.5-5.6 18-55mm AL (there is no * beside the DA), and the prime lens I have is SMC Pentax-M 1:3.5 28mm.
Based on what you've mentioned, would it be safe to say then that I'm better off using the kit lens?

Joseph
Forum: Pentax SLR Lens Discussion 09-09-2015, 07:17 PM  
18-55mm 1:3.5 VS 28mm 1:3.5 (Is there a difference?)
Posted By joseph_me
Replies: 17
Views: 2,528
Hi everyone,

First off, I'd like to say that I'm still learning about all these fun terminologies and the theory. Any help is appreciated!

So I have the k100D with the kit lens, 18-55mm 1:3.5. Recently I got as a gift an old k mount 28mm 1:3.5 (Which I'm still struggling to learn how to use on my camera, because it's all manual).

Is there a benefit of even using that 28mm lens? I figure if I wanted a wide angle shot, I could just use the kit lens at 18mm and still have the aperture at 3.5, so would it be correct in saying that I get a wider angle for the same aperture opening?

Thank you for all your input!

Joseph
Forum: Welcomes and Introductions 09-09-2015, 07:01 PM  
Hello from an excited newbie
Posted By joseph_me
Replies: 15
Views: 1,320
Hi all,

I loved photography as a kid, and with a cheap digital camera I took pictures of everything. I had a pretty huge collection of pictures too. I've lost all of those, however, when our hard drive got fried. I was devastated, and never took much pictures after that.

Well, that's all about to change! I'm getting back into it. I hope this forum will help me to progress well, and I hope someday I could contribute in a small way.

Thanks for letting me come on board.

Joseph
Search took 0.00 seconds | Showing results 1 to 12 of 12

 
Forum Jump


All times are GMT -7. The time now is 03:31 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top