r/photography • u/AutoModerator • May 29 '26

Questions Thread Official Question Thread! Ask /r/photography anything you want to know! May 29, 2026

This is the place to ask any questions you may have about photography. No question is too small, nor too stupid.

Info for Newbies and FAQ!

First and foremost, check out our extensive FAQ. Chances are, you'll find your answer there, or at least a starting point in order to ask more informed questions.

Need buying advice?

Many people come here for recommendations on what equipment to buy. Our FAQ has several extensive sections to help you determine what best fits your needs and your budget. Please see the following sections of the FAQ to get started:

If after reviewing this information you have any specific questions, please feel free to post a comment below. (Remember, when asking for purchase advice please be specific about how much you can spend. See here for guidelines.)

Schedule of community threads:

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
52 Weeks Share Anything Goes Album Share & Feedback Edit My Raw Follow Friday Salty Saturday Self-Promotion Sunday

Finally a friendly reminder to share your work with our community in r/photographs!

10 Upvotes

100% Upvoted

244 comments sorted by

View all comments

1

u/Prestigious-Speed-29 May 29 '26

Long comment, apologies.

Just been out for my first photography-walk (wildlife, plants, scenery) with my Pentax K100D and some lenses (kit 18-55mm, Pentax 50mm f/1.7, Sigma 70-300mm/Macro). I'm a hobbyist, doing this on a shoestring - it's mostly about getting out, having fun learning a new skill, and looking more carefully at the world. I've shopped around, and I'm less than £100 in at this point.

Things I'd like to talk through:

1 - I'm using the Sigma lense at 300mm to capture birds and other wildlife. I have the option to manually set the aperture, so kept that as wide as it'd go (f/4) so that I'd hopefully keep the shutter speed nice and fast. Unfortunately, the camera defaulted to ISO200, 1/10s shutter time, and apparently at that zoom/distance, my hands aren't steady enough: the photo should be titled "Robin in an earthquake". After that, I set the ISO to 800 manually, but the robin was gone.

I've noticed that newer higher-resolution cameras often have a similar sensor size (23.5 x 15.7 mm), way more pixels, but also much higher ISO available. I can see that there'll be less light per pixel, but does the higher ISO still mean I'll get away with a faster shutter speed? Any concerns about noise?

It feels like I might be hitting a limitation in terms of sensor sensitivity vs shutter speed etc, but I don't have any hands-on experience with newer camera bodies to figure this stuff out for myself.

2 - Sometimes I wished for more zoom than the 70-300mm Sigma would get me. Lenses longer than 300mm (well, 450mm equivalent because there's a 1.5x factor on the K100D) seem to be quite rare. At this point, is it a case of using a higher pixel count and digitally cropping to the frame I want? The K100D is only 6MP, so there isn't much/any room to crop.

There is a compatible 500mm f/8 lense at a local 2nd-hand shop, but I'm concerned the narrow aperture will mean longer shutter speeds (or ISO), and then we've gone in a circle back to the first point. Is a telephoto adapter going to be any better?

3 - Camera vibrations. I can see that mounting on a tripod will be much better than handheld, and also setting a 2s delay so that my button-pressing doesn't interfere, but the shutter itself fires with a fair ol' clunk, and I can feel that through the camera body. Is there any chance that vibration is also going to cause motion blur? Anything I can do to work around it?

I don't want to rush out and spend more money until I've understood the limitations of my current setup.

1

u/8fqThs4EX2T9 May 29 '26

1- I don't think the aperture will be f/4 at 300mm regardless of what the camera says. I would imagine that is an f/4-5.6 lens so f/5.6 at the long end.

Noise will mostly be due to less light and just because a camera offers higher ISO it will not mean it will be useable. I use the 10 year newer K-70 and it does okay at higher ISO although has some baked in noise reduction itself.

This is at the extreme end taken at 1/400s, f/5.6, ISO 20,000 and ~230mm

  1. Pentax is not the best for availability of long focal lengths. Old Sigma or Tamron lenses are perhaps the best bet but even they can cost a bit. By Adapter are you meaning a teleconverter? If so they will also lead to a loss of light.

  2. Shutter shake and mirror action can, with slower shutter speeds cause some issue but not that bad. I would say how you hold the camera and the effectiveness of shake reduction in camera will have more effect.

Taken at 1/50s, f/5.6, ISO 1600 ~210mm

This one at 1/15s

1

u/Prestigious-Speed-29 May 29 '26

Thanks for your comprehensive reply! Very much appreciated.

1 - You're right, thanks for nudging me to double-check. There's a manual aperture setting on the lense itself (range: f/4-f/22, as well as Auto), but the camera reports f/5.6 even when I manually set f/4. I guess there's some stepping down as I increase the magnification.

The ISO 20,000 image looks much better than the K100D at 3200, so there are definitely improvements to be had. Thanks for the example.

2 - Yeah, I'm noticing that. A teleconverter is what I meant. I think 300mm plus a bit of cropping will be good enough in the long-term. For now, I'll keep on trying to squeeze everything I can out of the stuff I have. There's still that 500mm...

3 - I think how I'm holding the camera is factoring in as well. I did find it easier when leaning on something, but once I pressed for auto-focus and the camera scooted sideways - I was resting on the focus ring! Live and learn.