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Forum: Sold Items
06-16-2017, 05:53 PM
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If you're wanting front fill, then you can run with a flash on top of the Cactus unit. That top flash unit can be master, slave, etc. The Cactus V6 IIs allow for P-TTL pass-thru. Even better, with the latest firmware, as these have, should even transmit P-TTL.
I've Elinchrom BRX500 studio lights, with a Skyport remote so the Cactus could go on the camera first, and then Elinchrom control on top of that. With that setup, I could run 5 lights remotely from my camera. Really slick scenario, but not needed in most conditions.
What would you like to accomplish? I often used lighting for group photos and headshots. That's where much of my lighting experience comes from.
---------- Post added Jun 17th, 2017 at 05:16 ----------
2 sold, 2 pending sale
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Forum: Pentax DSLR Discussion
05-31-2017, 08:53 AM
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Lenses used to have a very large distance between the f-stops at the full open end (fmin), becoming successively smaller towards the most closed end (fmax). Now they are generally equally spaced. For one that is equally spaced, it likely is:
percent travel = L/Lmax *100% = (log f - log fmin)/(log fmax - log fmin) * 100%
BTW my basis is: travel distance L is proportional to log of f-stop, and then I used a linear interpolation formula for L going from L=0 to L=Lmax
---------- Post added 05-31-17 at 09:29 AM ----------
If you rather not use logarithms you could number the f-stops starting with 0. E.g., if it goes from f/2.8 to f/22:
f/2.8 --> N=0, f/4 --> N=1, f/5.6 --> N=2, f/8 --> N=3, f/11 --> N=4, f/16 --> N=5, f/22 --> N=6
and replace the log f/stop by N in the equation.
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Forum: Pentax DSLR Discussion
06-20-2016, 07:17 AM
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To only delete images and not format the card and lose other stuff such as gps logs, go to playback (i.e. to see wha'ts on the camera) -> menu -> delete all images, it's at the bottom of the first menu list.
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Forum: Pentax Camera and Field Accessories
06-14-2016, 01:55 PM
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I was able to take the focussing screen I purchased for my k30 and install it in my k3 without issue. Since the k50 is essentially the same camera I don't see why you would have problems with your k3
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Forum: Pentax Camera and Field Accessories
06-14-2016, 02:13 PM
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Just to include a couple newer bodies, the following bodies all use the same screen: K-7, K-5, K-5II, K-5IIs, K-3, K-3II, K-30, K-50, K-500, K-S1, K-S2, and K-70. (2017: Add the KP.)
An easy way to verify is to look at the accessories available for each camera on the official Ricoh Imaging / Pentax website. They all list the MF-60, MI-60, ME-60, and ML-60 screens (they are all matte screens, just with different bracket lines).
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Forum: General Talk
11-26-2015, 12:26 PM
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This is my current favorite, a Casio Oceanus. Titanium and sapphire, atomic and solar power. High tec in a low key design.
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Forum: Pentax News and Rumors
02-17-2016, 03:08 PM
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Me at this moment:
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Forum: Pentax DSLR Discussion
01-24-2016, 02:38 AM
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I come across this all the time with older lens. I am pretty sure the iris is a little sticky and not responding at a consistent speed. So when when you press the green button it is not metering correctly and when you shoot it responds differently. Try (with a M lens) by not quite clicking it home (unmounted by 7-8 mm) and set the camera to AV and see if you get a correct exposure. This trick means the body can not reach the aperture lever of the lens so the lens works manually just like an old M42 does. I think a lot of M irises are sluggish so this is how I use them.
Another issue that threw me a lot (until I worked it out) is that you tend to hold the camera away a little to find the green button and with your eye off the viewfinder light can pour in there stuffing the exposure reading. I think it is ridiculously poor design that light can enter that way and stuff up basic metering.
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Forum: Pentax SLR Lens Discussion
12-29-2015, 03:53 PM
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These are normal idiosyncracies of the PKA mount IME.
1. Camera reads down to f2.4 with a PKA mount on all the f2.5 lenses. However this is a bit of a non-issue, the difference is small enough to not really affect anything. At f2.4 on the camera the lens will be wide open ie f2.5. Then at eg f8 the lens will actually be at ... ?f8.2 or something like that.
2. +1Ev compensation is typical I just expect to have to dial in something like that. Chimp a couple of shots when you mount the lens to get an estimate. In practice I find that I have to readjust the ev comp if I move from eg wide open to f11. I have got into the habit, when testing lenses across the aperture range, of using M mode because of this.
I should mention that these inconsistencies can be experienced with any non chipped PKA mount MF lens, not just adaptall lens + PKA mount. It's the camera really....
To check the operation of the mount, use a subject like a grey card or uniformly lit whitewash wall. In these circumstances the camera + mount + lens should show more or less consistent metering, once an Ev comp has been set, between M and Av, and from wide open through f16 in Av - maybe half a stop variance.
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Forum: Pentax SLR Lens Discussion
12-29-2015, 03:10 PM
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There are fixed aperture values based on the last mount limitations.
See this:
Features and Operation of the Ka Mount
But that doesn't explain 2.4 nor exposure issues.
Exposure issues happen for me also. Some a series lenses give me trouble also. Center vs matrix could contribute to errors.
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Forum: Pentax SLR Lens Discussion
01-19-2016, 04:45 PM
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You hit it in the title for the thread. Lens design goals set the constraints for lens size. Here a few factors that influence lens size:- Focal length
- Flange focal distance (distance from lens mount face to focal plane)
- Image circle
- Maximum absolute aperture (the size of the physical opening)
- Retrofocal vs. Telephoto* vs. Symmetrical design
- Sophistication of and/or decisions made for corrective design elements
- For zooms, fixed vs. variable maximum aperture
- Zoom range
- Internal drive motors
- Internal shake/vibration control
- Internal focus helicoid
- Aperture mechanics
All other factors from the above list staying constant:- Longer focal length tend to result in longer lenses
- Longer flange focal distance tends to result in larger lens
- Larger image circle generally means larger lens
- Larger maximum aperture generally means larger lens
- Retrofocal designs (required for wide angle lenses on most SLRs and many mirrorless cameras) tend to be larger
- Telephoto designs* (common at longer focal lengths) are more compact than a symmetrical lens
- Well-corrected lenses tend to have more elements and are thus larger than poorly corrected lenses
- Fixed maximum aperture zooms tend to be larger than variable aperture of the same focal length range
- Big zoom range results in big zooms
- More stuff (motors, focus mechanisms, aperture mechanisms and what not) means larger size
Of course, there are exceptions that prove almost all generalizations on the above list. Those would include "pancake" primes and many wide angle lenses. For example, I have a Vivitar 28/2.5 in M42 mount that is a full 3" (74mm) long with a 67mm filter ring. I also have an Adaptall-2 mount Tamron 28/2.5 that is half that size and only takes a 49mm filter. The Tamron is the better of the two lenses by a large margin. Go figure...:p
Steve
* The term "telephoto" is commonly used as a synonym for focal lengths longer than "normal", but that use of the term is not technically correct. While such lenses often use telephoto design the term has little to do with focal length. In a telephoto design the optical center and rear principal plane are located forward of the physical center of the lens allowing for a shorter overall length than if the lens were of symmetrical design. For a good discussion see: http://coinimaging.com/telephoto.html |
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Forum: Pentax SLR Lens Discussion
01-19-2016, 04:04 PM
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In the case of your example, the 14mm is considerably larger not only because of the faster aperture, but also because it's wider. Even 1mm is pretty significant at the wide end, at least from a perspective of optical design.
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Forum: Troubleshooting and Beginner Help
01-08-2016, 11:42 AM
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Pentax Slide Copier and SMC-K 50mm macro lens
My current setup:
 My Filmcopier Rig I by Lars Holte, on Flickr
Works great for colour slides and B/W negatives. Colour negatives is another matter because of the orange layer. Negative scanners have film profiles that take care of that when you use a proper scanner, but getting the colours right when photographing colour negatives is problematic.
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Forum: General Photography
12-20-2015, 12:44 AM
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Not sure if this will replace my Pentax DSLRs or if this is the future of photography, but the tech and concept look interesting :
https://light.co/
For $1699, it might be a bit expensive to try one...
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Forum: Troubleshooting and Beginner Help
12-30-2015, 08:29 AM
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Pentax always recommends turning it off on a tripod but I can't recall an official reson from them. The SR system entering a 'feedback loop' of trying to detect and correct shake that wasn't there in the first place is the usual reason cited by 3rd parties. You can always try both and see if you can tell the difference.
And yes, it is automatically disabled in a few situations where the camera assumes a tripod is in use - the Self-timer, IR Remote Control, Mirror Lock up, Bulb mode, and maybe some I'm missing. As far as I can tell, SR is still active with a cable release (outside of the previous cases).
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Forum: Pentax K-30 & K-50
12-29-2015, 02:34 PM
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Just curious, do you realize that using viewfinder and Liveview to focus are not the same? as one uses PDAF and the other uses CDAF; separate focus mechanism on the camera.
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Forum: Pentax K-30 & K-50
10-23-2015, 11:27 AM
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But the Wasabi is at the full voltage and the Li109 (K50 battery not K3) is listed as 1400mAh not 2300mAh and in practice it actually lasts a bit less than the 1050mAh original Pentax battery which leads me to rate it at about 900mAh. I think the more important point is that the AA's are drawn down collectively (in series for voltage) which means the total capacity is equal to the capacity of a single battery (2000mAh or 2200mAh depending on the AA's you have). Essentially a set of AA's has close to 2x the mAh of the Li-Ion OEM battery and slightly more than 2x the Wasabi from practical experience. But the Lithium non-rechargeable AA's are even stronger (3000 mAh or so) and they are less sensitive to drain rate. Ni-Mh AA's drained too quickly (by lots of live view) will have only around 1000mAh capacity.
http://data.energizer.com/PDFs/l91.pdf |
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Forum: Pentax DSLR Discussion
06-09-2015, 08:32 PM
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Who told you that you need to upgrade?
And what are you looking to do that the k-50 does not do?
The k-50 is still fairly current and though there are newer bodies it is best to understand where you want to go before upgrading. You should have a good idea of what is holding you back with the k-50 before spending money on a new body. Perhaps your need would be better met with a new lens, or a flash or a tripod rather than a new body.
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Forum: Pentax Price Watch
06-02-2015, 09:22 PM
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Forum: Pentax Price Watch
05-31-2015, 01:01 AM
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Looks like no flash in that link?
Bundle of 50mm for free though?!
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Forum: Pentax Camera and Field Accessories
05-12-2015, 07:28 AM
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Let me post up a photo real quick...I want you to see just how tight it is....give me a few minutes.
Ok...here it is. I stuck a Ruler to show actual size. The shoulder straps are zipped together in the picture. Hope this helps.
I also just ordered the CLIK Elite Compact bag above several posts , so I can comment on it later if needed but its at least twice as big as this one.
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Forum: Pentax Camera and Field Accessories
05-11-2015, 04:36 PM
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I just got my ILC Bag from Precision. Its Small ! The Body Does Not fit at the top. It has to be lens pointing up with body resting in the bottom.
It can Hold a K3 , K30 , or a Ks2 with a lens up to about a Pentax F 70-210. It can hold one additional small lens at the most unless tiny primes and then maybe up to 2 at Most.
There are pockets for a small flash at best , batteries , a couple cards , lens accessories , Phone , etc. and very tight and compact. For $19.99 shipped Im sure not complaining at all......I like it !
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Forum: Pentax SLR Lens Discussion
05-07-2015, 05:58 PM
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I have never thought of doing that and I have never had a problem. The likelihood of stripping or just wearing out the internal focus drive gearing is much higher since it is often plastic. But I have never experienced that either.
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