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Forum: Pentax SLR Lens Discussion 01-20-2016, 06:44 AM  
Cheap 200-300mm options
Posted By russell2pi
Replies: 47
Views: 3,532
Well thank you all, I got the 55-300mm (thanks Des for the ebay tipoff) and racked it out to 300mm while thanking her for the 'gift', and now she's convinced it's a "pen is extension" ;) No amount of reasoning around the f-number, brand name or "DA-L" designation will convince her :) Especially when I told her of the cute birds I nailed in my first two test pics (Acridotheres tristis and Sturnus vulgaris).
Forum: Pentax Forums Giveaways 01-16-2016, 04:10 AM  
READ ME! Pentax Tips from the Community (55-300mm Giveaway)
Posted By russell2pi
Replies: 773
Views: 90,777
Forget about "cameras, lenses, technique, accessories, post-processing". As they say: f/8 and be there. Take a camera, any camera, everywhere you go, and be ready to use it.
Forum: Pentax Forums Giveaways 01-09-2016, 02:10 AM  
Chistmas 2015 Giveaway.
Posted By russell2pi
Replies: 31
Views: 2,836
Is the DA 55-300 giveaway still happening?
Forum: Pentax SLR Lens Discussion 12-27-2015, 05:07 PM  
Cheap 200-300mm options
Posted By russell2pi
Replies: 47
Views: 3,532
Now just to wait for the competition :cool:
Forum: Pentax SLR Lens Discussion 12-25-2015, 04:02 PM  
Cheap 200-300mm options
Posted By russell2pi
Replies: 47
Views: 3,532
Thanks again all - after chewing it over I might go for a S/H DA-L 55-300mm. The reason the budget was strict was it was to be my xmas present (family man..!) but if I make it also my birthday present I can manage it. Everything cheaper feels like too much of a compromise for what's not a massive price difference at the end of the day.
Forum: Pentax SLR Lens Discussion 12-20-2015, 07:57 PM  
Cheap 200-300mm options
Posted By russell2pi
Replies: 47
Views: 3,532
Thanks for the comments so far. I would love a DA 55-300 but most Marketplace sellers won't ship outside US, and ebay and the like seem to be all well over US150 + 20-40 for postage so it's more than a little stretch to my budget.

There is a locally available Tamron AF 70-300mm F/4-5.6 Di LD Macro 1:2 I'm looking at.

Otherwise I think 300mm might be outside my budget and would be better with the DA 50-200mm or F 70-210mm. ?
Forum: Pentax SLR Lens Discussion 12-20-2015, 05:16 PM  
Cheap 200-300mm options
Posted By russell2pi
Replies: 47
Views: 3,532
Hello, I am looking to add a cheap lens in the 200-300mm range. $100 budget, tops. I know it won't be good in that price range but what is least bad? I keep chasing my tail looking at reviews and what's available used.

I would mainly use it for perched birds. I doubt it necessarily needs to be a zoom as I guess more often that not I'll still end up zooming all the way and still cropping. MF is no problem. I enjoy old lenses but wouldn't prioritise that over image quality.

After going through various thoughts I think I'm kinda just leaning back where I started, the DA 50-200mm. Is that a very bad idea?
Forum: Troubleshooting and Beginner Help 01-20-2014, 04:23 AM  
Question about DOF on reflected surface
Posted By russell2pi
Replies: 26
Views: 1,735
Nice point Tanzer. The ballpen is something like a 0.25 mm lens.. of course it has incredible DOF!
Forum: Troubleshooting and Beginner Help 01-19-2014, 04:01 AM  
Question about DOF on reflected surface
Posted By russell2pi
Replies: 26
Views: 1,735
Sure -- but there's probably no need to have kittens over the issue.
Forum: Troubleshooting and Beginner Help 01-17-2014, 10:02 PM  
Question about DOF on reflected surface
Posted By russell2pi
Replies: 26
Views: 1,735
The other thing I forgot to mention when it comes to convex mirrors like your ballpoint pen.

All images will be at most one focal length behind the mirror (which is one quarter of the diameter of curvature).

So in your example, let's say the ball had a diameter of 1 mm. So long as you had 0.25 mm of DOF and you focussed correctly, you could have the entire reflected scene in focus from zero to infinity.

Pretty tricky. Hadn't really occurred to me before but pretty easy to show with ray diagrams or the lens equation.

Edit to add: mind you, ray tracing and the lens equation are both generalisations for a "thin" lens/mirror so it will start to break down towards the edges of that very curved surface.
Forum: Troubleshooting and Beginner Help 01-17-2014, 07:53 PM  
Question about DOF on reflected surface
Posted By russell2pi
Replies: 26
Views: 1,735
You can think of the scene you see in a reflection as being for all optical purposes like a 3D object located behind the mirror: the image. This is because rays of light emanating from the real object, no matter what direction they are going in, reflect off the mirror at such an angle that they appear to have come from the direction and distance of the object's image and therefore behave in exactly the same way as if they really did come from an object located at the image.

(A not all that helpful explanation and diagram is at Virtual image - Wikipedia, the free encyclopedia )

For a plane mirror, distance from the image to the mirror equals the distance from the object to the mirror. That's when the rule you quoted about the sum of the distances would apply.

For a convex mirror, the image is closer (but smaller than the object - see pic on wiki page) so the focal distance will need to be shorter than the sum and the DOF will be that you expect of a (smaller) object at that (lesser) distance.

For concave, it's potentially vice versa (but it gets more complicated here with inverted images etc - see Curved mirror - Wikipedia, the free encyclopedia ).

If you really wanted to do the calculations to work out your image distance and DOF (I wouldn't... talk about spoiling the fun of photography :) ), it can be done pretty easily. Let f = focal distance = half of the radius of curvature of a spherical mirror. Then the lens equation, 1/f = 1/u + 1/v will allow you to take the distance (u) from any point on your object and find out the distance (v) between the mirror and the corresponding point of the image, or vice versa. (v will be negative if the image is behind the mirror)
Forum: Lens Clubs 01-16-2014, 02:30 PM  
The M Club!
Posted By russell2pi
Replies: 7,146
Views: 1,050,861
M50/1.7 plus extension


Rose by russell2pi, on Flickr
Forum: Mini-Challenges, Games, and Photo Stories 01-11-2014, 07:56 PM  
Other Challenge +Show us your bokeh+
Posted By russell2pi
Replies: 4,919
Views: 419,843
Forum: Lens Clubs 01-08-2014, 08:53 PM  
The M Club!
Posted By russell2pi
Replies: 7,146
Views: 1,050,861
M50/1.7 and Pentax Auto Extension Tube

Forum: Photographic Technique 04-12-2013, 05:07 AM  
fishing photography?
Posted By russell2pi
Replies: 12
Views: 1,042
Don't be afraid to take the polariser off. Sometimes you actually want to see the reflections instead of the fish :).
Forum: Photo Critique 04-12-2013, 05:03 AM  
Misc Under the Southern Cross
Posted By russell2pi
Replies: 16
Views: 1,321
The writing continued on with other stuff contrary to my purpose. (Actually, I thought about photoshopping in a question mark at the end....)

The flare - well actually it was a fluke. I didn't consider it until after this exposure. I took a few after it while shading the front element but I do think you're right - partial shading might have given the effect more subtly and with less noise. I did revisit the scene 4 times but only the other three were in daylight. This one I shon an LED light on the monument - hence the blue colour on the top.
Forum: Pentax DSLR Discussion 04-12-2013, 04:50 AM  
Cameras cameras cameras
Posted By russell2pi
Replies: 16
Views: 2,274
LOL - you must be old. My bank freebees always had written on them "Call now- you have been pre-approved for a $10,000 credit card!"

But yes I agree - if you absolutely can't do it with a K5+kit, either you are choosing a very particular specialty, or you're wrong.
Forum: Pentax DSLR Discussion 04-12-2013, 02:14 AM  
Cameras cameras cameras
Posted By russell2pi
Replies: 16
Views: 2,274
I bought a K-5 II recently... if I scored a PTA (Permit To Acquire) from the Mrs the money would go on more lenses just to extend my focal length range. Not a new body. (Or - potentially, buy some babysitting time with the money.) I certainly find in my own pics and most I see on the internet, artistic judgement is the limiting factor, not technology / resolution.
Forum: Photo Critique 04-12-2013, 12:49 AM  
Misc Under the Southern Cross
Posted By russell2pi
Replies: 16
Views: 1,321
Well I entered it and it won the local content category.

Now I'm feeling guilty I may have led flag-waving cheerers into assuming my message was straightforward glorification. Do I secretly offend them by augmenting that line of of thought with other conflicting interpretations? Hopefully not. From what I understand of Australian history, the further one goes back in age or history, the more equivocal the position becomes with regard to our involvement in the Great War (notwithstanding respects paid for the sacrifices of those who served). I've not met the judge but the organisers of the show are all retirees. Hopefully they get it!
Forum: Lens Clubs 04-09-2013, 09:14 PM  
The M Club!
Posted By russell2pi
Replies: 7,146
Views: 1,050,861
I'd be interested to know more about the firefighter's helmet and branch (nozzle) - is it a memorial of some sort?
Forum: Weekly Photo Challenges 04-08-2013, 01:45 PM  
Project 52 P52-5-15 Winner - Perspective - Nifty Fifty
Posted By russell2pi
Replies: 13
Views: 977
I figured out a quick fix... go into the address bar and delete the 's' in https://... press enter, and voila. I'm not sure how I came to be in https mode in the first place. All the links in the email alerts are http, and I wouldn't key in https manually. I use EFF's HTTPS Everywhere plugin but it doesn't seem to work with this site anyway (thankfully). Ah well.
Forum: Post Your Photos! 04-08-2013, 02:40 AM  
Black & White Piano Recital - Little Girl in a Big Scary Place
Posted By russell2pi
Replies: 23
Views: 1,429
Lovely :)
Forum: Photographic Industry and Professionals 04-07-2013, 06:42 AM  
Snapshot DSLRs
Posted By russell2pi
Replies: 26
Views: 1,861
Nah- this is in Australia, so most had Sigma's latest 0-1000mm f/22 superzoom because importer markups are so horrendous that no-one can afford Pencanikon lenses. (Actually I think the pentax kit lens isn't too bad.)



Oh, god, yes I hate that... even when I retired my film gear and stuck with the $99 P&S... "Wow-you must have a great camera! What brand is it?"



Really? With a mirror to flip and a bigger sensor, therefore bigger lenses, I wouldn't have expected any time advantage to DSLRs?
Forum: Photographic Industry and Professionals 04-07-2013, 05:48 AM  
Snapshot DSLRs
Posted By russell2pi
Replies: 26
Views: 1,861
I have to admit to being a little bit peeved.

Recently, for work, I was dragged through a series of ugly tourist attractions (theme parks). I didn't bother to bring a camera. I was surprised to see that very many people including young teenagers were casually toting DSLRs, the likes of which I have waited for years and years and years, as a family man, to acquire permission to purchase without an accompanying divorce certificate. And what were they using them for? Snapshots of spongebob squarepants, assorted animals forced into a life of slavery, etc. (Somehow we're not allowed to eat aquatic mammals but imprisoning them for life and forcing them to perform tricks for food is fine and dandy.)

Yeah ... envy -- not attractive... I know.

The question remains, though - do DSLRs offer Auto-mode JPG shooters any advantage? I was surprised to see the cashed-up crowd carrying them. I would have thought in casual use (auto mode) they'd get better images and far better handling out of a compact, or even their phones.

So my question is - auto mode on a DSLR vs auto mode on the best compacts, in the hands of a snapshooter. Which is more likely to yield satisfactory results, and if DSLR, is the benefit worth the inconvenience?
Forum: Post Your Photos! 04-07-2013, 04:05 AM  
Landscape Where is the sun?
Posted By russell2pi
Replies: 7
Views: 631
Jeetjes ... I lived in the Netherlands for a few years (happy memories)... never in more than about 75 square metres. Very nice! Are they cows? They seem very wooly.
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