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Forum: Post Your Photos! 1 Day Ago  
People Algonquin Park, Family Day Weekend
Posted By BrianR
Replies: 21
Views: 418
The bottom one is aces for a more natural setting:). Standard photography advice is to have a small stepladder handy for different viewpoints or getting level with things. Obviously it's advice for people without massive Ontario snowbanks. I did notice the eye-level viewpoint and just assumed it was lowish in the tree, the snowbank backstory definitely adds to the special:D.



Looks ready for a playful pounce:). I could see hanging out with the Pine Martens eating up a ton of time.
Forum: Pentax SLR Lens Discussion 1 Day Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
It's been on my to-do list, so I figured I'd check it off. Detailed results are here: Magnification of DFA100mm + Raynox 250 - PentaxForums.com

At min. focus distance, the dfa50mm&DCR250 will give 1.32X magnification and a working distance of about 25mm. At infinity focus, it's 0.42x mag. and 111mm working distance (measurements are approximate!).

It's not a combo I'd ever go out of my way to use. As you say, closeup filters are better suited on longer focal length lenses, and the dfa100mm being the size it is, I'll virtually always have it with me:).
Forum: Photographic Technique 1 Day Ago  
Macro Magnification of DFA100mm + Raynox 250
Posted By BrianR
Replies: 7
Views: 1,209
Thought I'd add the DFA50mm + DCR250, as expected the closeup filter's effect is much reduced on a shorter focal length lens. Working distance also becomes peanuts. As before, measurements are approximate, but the magnifications should be pretty good (subject to my ability to accurately line up the vague barrel markings). Units in mm. No test photos yet, I would probably need to be in a pinch to actually use this combo.

Barrel Marking 1/xFoV in mmMagnificationWorking DistanceFocusing DistanceInfinity560.42X 11123425520.46X10623010460.52X912185390.61X722074370.64X672023320.74X561952270.88X431881.5231.03X351861.2201.19X271861181.32X25189
Forum: Post Your Photos! 1 Day Ago  
People Algonquin Park, Family Day Weekend
Posted By BrianR
Replies: 21
Views: 418
I'm not a big fan of people, so that sounds like the ideal time:D.

Beautiful set of Pine Marten images, and thanks for the info. Knowing your subject is a big chunk of nature photography, and you've got that in spades here:).

I know there's usually a desire to exclude man-made objects from nature photos, but your first image here is my favourite (all are great!). I think it captures the setting well, the expression is terrific, and the light excellently shows their usually elusive habits with the sun on the face but rear in the shade. Fantastic detail & focus. I'll carry this one around as my mental comparison for the Algonquin Pine Marten photo standard:)
Forum: Post Your Photos! 1 Day Ago  
People Algonquin Park, Family Day Weekend
Posted By BrianR
Replies: 21
Views: 418
They all look good for me now, no broken links:).

What's the Pine Marten situation in Algonquin? Is it a lone individual or family that everyone goes to photograph or are there a few fairly tame ones?
Forum: Post Your Photos! 1 Day Ago  
Macro A few more snow crystals
Posted By BrianR
Replies: 9
Views: 303
Nice! I didn't realize you also had that AmScope 4x. I'm pretty happy with mine, and it's phenomenal at the price. My main goal is insect parts, but I just posted a couple of snowflakes:).

What is your 10x objective?
Forum: Pentax News and Rumors 1 Day Ago  
Stealth KP
Posted By BrianR
Replies: 42
Views: 4,103
Stick the 35mm macro on it and you can finally get that flying bat macro from 1cm away:D
Forum: Post Your Photos! 1 Day Ago  
Macro A stab at Snowflakes
Posted By BrianR
Replies: 4
Views: 129
I've been working on upping my high-magnification photography game and it was snowing yesterday, so I figured I'd give snow a whirl while I had the chance. These are my first stabs at flake closeups, I'll be trying again.

There is always the question of "why bother?" when other people have done it far better than I probably ever will. One is the technical exercise, and I freely admit enjoying overcoming the obstacles. It is a different challenge from non-moving insect parts as speed is somewhat important. No matter how cold you try to keep everything, they sublimate fairly quickly. It as also an exercise in colour. I opted for a light blue background with a hint of yellow fringe. The yellow ended up a bit mustardy, but I have a nice pile of colours to choose from and play around with for next time:). But the main reason for me is my ongoing fascination with ice, and the various ways it forms (and here unforms before my eyes). Ken Libbrecht's Snowflake Field Guide is a highly recommended read for anyone interested in snowflakes or even just ice formation in general. Seeing the stuff he describes with my own eyes makes it worthwhile.

The lens is the bargain AmScope 4x that I read about here. I imported it from AmScope through the US Amazon and it came to just over $40CAD after taxes etc. Still a massive bargain and my intended use with insect bits and pieces, but also works well on snowflakes. It's living on m42 extension tubes. More technical details in the flickr links for the interested.

The first one involved a bit of cropping (it's ~1.8mm high), if the next flakes are this small I will be trying this AmScope on my smaller sensored but harder to work with Nikon J1. Maybe a Q of some sort (with its lovely little flash hotshoe) is in my future?


Snowflake by Brian Robin, on Flickr


A Crystalline Entity by Brian Robin, on Flickr
Forum: Pentax News and Rumors 1 Day Ago  
Stealth KP
Posted By BrianR
Replies: 42
Views: 4,103
Why have shiny chrome features showing? This greatly limits the wildlife applications for the stealth features on this camera. Bat photographers will rejoice as it should confuse echolocation (but beware glints from a full moon), but that's about it. I guess underwater dolphin photographers might find it handy, but talk about a niche market.

:D
Forum: Photographic Industry and Professionals 1 Day Ago  
Plagiarism rears its ugly head ...
Posted By BrianR
Replies: 39
Views: 1,196
The Bonsai tree on the stylized heart is my favourite. It's pretty convincingly that other chaps photo from flickr (which he has freely allowed the use of in many illustrations), but it comes with the heartwarming:) backstory of it belonging to Saad's mother. That shows the extra level of commitment beyond just silently appropriating and taking credit for the work of others.
Forum: Pentax K-70 2 Days Ago  
Help choosing a flash for point and shoot and maybe a little more
Posted By BrianR
Replies: 11
Views: 317
Here's an example of @mcgregni of a simpler setup with results a billion times better than the direct on-camera deer in headlights flash: Indoor Exposure Mixing - PentaxForums.com

ps. I'm making this post in part to call Nigel (mcgregni) in and also point out that he has many great examples of photographing his kids in the flash section. The big-flash used in that thread might be larger than you're after:).
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
Nothing I said disagrees with your extension tube tests, just how you've said close-up filters affect things. Throw your Raynox into the mix, and try it out:). Be clear in the settings of your macro lens + Raynox and what magnification you're getting, metered light reading, etc.
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Size comparison: Pentax D-FA 100 WR macro vs. FA 100 macro
Posted By BrianR
Replies: 60
Views: 2,469
Have you ever done side by side comparisons? I've asked a few people regarding the DFA100mm WR and the non-WR model and few seems to care. You 'get' that it's the out-of-focus highlights and not the general mashed out of focus areas where the aperture shape matters the most, so I figured I'd ask. Actually, this could be a job for Ash whose time I have already imposed upon:). The FA100 looks to have the same 8-blade aperture design as the non-wr dfa100mm, but a comparison with the 9-bladed tamron would also be interesting:).

I ask because one of my initial photography loves was frogs in ponds, so plenty of out-of-focus highlights and also often plenty of light/dark edges. So I'm often confronted with the choice of stopping down to reduce the CA but then losing out on the slightly annoying octagonal highlights.
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Size comparison: Pentax D-FA 100 WR macro vs. FA 100 macro
Posted By BrianR
Replies: 60
Views: 2,469
No worries! I just thought my example (and I have several more like it, some even worse) flew in the face of the sentiment that "the CA is not that bad":D.



So, that's the thing. I do tend to avoid these situations, but at the same time it's somewhat annoying having to alter my preferred compositions or lighting arrangements due to a lens deficiency. I understand it's a compromise for having such a tiny package, and I absolutely adore both my dfa macros as they are:).

As you say, it performs up to expectations, but it is also important to be realistic with those expectations and to take into account how often (if ever!) you'd be using it in less optimal situations that highlight its weakness.
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
Doundounba is a master of this combo, if you haven't already trawled his flickr stream go back to his post in this thread. Raynox should probably give him a commission:)

For reference, I made a little chart showing the magnification & working distance of the dcr250 when coupled with the dfa100mm you might find useful. Calculators are handy but do make assumptions about simplified lens constructions, this is based on practical tests:

Magnification of DFA100mm + Raynox 250 - PentaxForums.com
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Size comparison: Pentax D-FA 100 WR macro vs. FA 100 macro
Posted By BrianR
Replies: 60
Views: 2,469
The DFA50 seems to outperform the DFA100 in the CA department (and a bit in the sharpness department). At least, in a year with the dfa50mm I've yet to see any CA I strenuously objected too, but I also haven't made any attempts to seek out and find it in the situations where the dfa100 gives me pains.

No one has commented on my CA example, it's the last post of page 3 so these sometimes get lost. Please go look, and tell me if this sort of CA on the DFA100mm is reasonable:), keep in mind it is the entire image and not a crop.
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
This might help with the light loss & DoF discussion. Same light on the ruler, 1:1 mag in each shot. DFA100mm@2.8 on bellows in the top photo. DFA100mm & DCR250 in the bottom two, f/5.6 in the middle, f/2.8 in the bottom (apologies as it appears I bumped the ruler and slightly increased the angle, but it is still very representative of the DoF).






My own photography education is pretty random, some of it having been scrawled on the sides of cereal boxes or bathroom stalls. I try to keep an open mind that I could be utterly wrong about pretty much everything, so I always take it as a good sign when you agree with me, or what you say jibes with what I think I know:)
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
Are you saying extension tubes don't increase the effective f-stop? Please be specific. Refer to the links I provided and point out what parts you disagree with.



The one responding to UncleVanya's comment about closeup filters? Where you gave examples using only extension tubes and not closeup filters?

My own tests show (at the same light source, iso & shutter speed):

DFA100mm focused @ infinity on 100mm of tubes to give 1:1 magnification is little over 1.5 stops underexposed compared to the same DFA100mm+Raynox DCR250 with the dfa focused to about 70cm (this gives 1:1 mag when coupled with the raynox).

Same magnification, same f/stop on the lens, the extension tube version is much darker than with the closeup filter. DoF is correspondingly less with the close up filter.
Forum: General Talk 3 Days Ago  
I don't know to laugh or cry...
Posted By BrianR
Replies: 54
Views: 2,518
It's known that NASA uses the Nikon D4 in space, which have a 13.1EV dynamic range according to DxO, ergo this should prove that the stars wouldn't be visible and definitively prove that the moon landing was real (and also prove the side corollaries that I only skim articles and completely ignore dates).
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
Sort of, but there's no free lunch. Tubes increase the effective f-stop. This reduces light but also gives you a hand by a corresponding increase to the DoF. If you want the same DoF with the closeup filter (which don't increase the effective f-stop), you have to stop the lens down by a comparable amount and the net result ends in a wash*. For more details on the applicable terms & conditions, see: Macro Extension Tubes & Close-up Lenses and also Macro Camera Lenses.

An achromatic close up filter will still be my choice over tubes, at least partly because I don't have tubes with aperture coupling and the filters are much easier to work with.


* note it's a a win for the closeup filter setup if you want a narrower DoF. But as magnification increases, this isn't usually considered a plus. However, more flexibility on the wide end does help avoid diffraction but stacking really gets mandatory.
Forum: Pentax SLR Lens Discussion 3 Days Ago  
Size comparison: Pentax D-FA 100 WR macro vs. FA 100 macro
Posted By BrianR
Replies: 60
Views: 2,469
DFA100 @f2.8 iso200, 1/250s, k5iis, no cropping, shot in raw and 'zeroed' preset in LR5 for a baseline:



The fringing is extreme on high contrast edges and wide open. It diminishes as either of these conditions lessen. I've learned to avoid these situations where possible, but when it isn't it can be tedious to protect other colour information while correcting for it. I understand it to be Axial Chromatic Aberrations, caused by different wavelengths of light focusing on different planes. Aberration gurus please correct me if I'm wrong:).

I accept it as a compromise of size and cost of the dfa100mm. I'm hoping with pentax's recent releases of super awesome performance no compromise lenses that a highly corrected macro will eventually turn up (and that I can afford it by the time it does:D). However, the only reason I would part with my dfa100mm is probably for a dfa100mm wr, I cannot imagine being without the option of its tiny size.
Forum: Pentax SLR Lens Discussion 5 Days Ago  
Size comparison: Pentax D-FA 100 WR macro vs. FA 100 macro
Posted By BrianR
Replies: 60
Views: 2,469
This is terrific, and will definitely help anyone looking for a comparison. I bought my dfa100mm sight unseen and was considering the FA100 as well. I made a couple of cardboard cylinders of their dimensions as I could not find a photo comparison:D.

If you wanted to add an extra touch, you could also throw in a shot of them both fully extended?
Forum: Pentax SLR Lens Discussion 5 Days Ago  
Size comparison: Pentax D-FA 100 WR macro vs. FA 100 macro
Posted By BrianR
Replies: 60
Views: 2,469
I'm not sure it's clear from what you quoted, but Allen's numbers are comparing a third lens that is not pictured, the often ignored original DFA100mm. I've never had mine side-by-side to the WR model (or their FA ancestor), but the numbers are essentially identical between the two dfa100mm macros..
Forum: Photographic Technique 5 Days Ago  
Studio Flash Calculator?
Posted By BrianR
Replies: 11
Views: 400
I suggested your camera be set to 1/3 steps so that it matches your flash. If you can set both to 1/2 steps, that's fine too. The most important thing for this thread is that they match.



Grids, snoots, flags, etc., if you can get the subject and background lights completely independent of one another and minimize the spill, it can make relative adjustments easier.

You're happy diving in to photoshop, so another possibility you might consider is combing the lighting in post. In your can photo, take a shot with only the front light on, then take another with the backlight how you like it but the front light off. Combine in post. I have an example of this sort of thing in the first post here, where I move a single light around and then blend the results: Lighting for wide angle close-ups - PentaxForums.com. My use was to be lazy and only pack one light, but this has legitimate studio use. That said, it's almost always more satisfying to get the physical setup 'right' and do it in one shot and generally necessary if your subject is alive and possibly moving:).
Forum: Pentax SLR Lens Discussion 5 Days Ago  
Any K mount lens that's more macro than macro (ie, micro)
Posted By BrianR
Replies: 38
Views: 1,191
Yup. I've used the tamron 1.4x TC with my dfa100mm with good results, and by all accounts the Pentax TC is better. This combo will give you 1.4x mag at the minimum focus distance. Alternatively, you can use the TC+DFA100 to get 1x mag but with a greater working distance than the DFA100 on its own.
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