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Forum: Sold Items 09-15-2012, 10:54 AM  
For Sale - Sold: Pentax SMC A 50mm f1.2
Posted By cps_goodbuy
Replies: 7
Views: 1,362
Pming
Edit: Pm'd :)
Forum: Pentax DSLR Discussion 04-30-2011, 04:31 AM  
Masters Degree Survey @ Pentaxforums.com
Posted By cps_goodbuy
Replies: 33
Views: 6,405
Thank you for your well wishes. I hope the reply below better explains the survey.

Surveys are dependant on the individuals that are willing to fill them in, thus there is this bias. Primary research will have some degree of bias that can not be entirely avoided. Bias is identified and factored in the formulation of the research method and then reduced or avoided in the reformulation of the research through testing. Examples of bias are researcher environmental impact, sampling impact, time period impact, interpreter bias etc. The survey was tailored to the area it intends to assess.

This primary research is centred on cluster sampling where there is a targeted segment to be surveyed, i.e. forum members. Also considered is the availability of those members that are willing to fill the survey in, and the snowball effect where additional members are referred to the survey.

This primary research is not a quantitative exercise, but a qualitative one.

The purpose of the questions are not to create statistics, assess individuals purchasing power, or quantify individual preferences, but to allow for me to extrapolate and critically assess the meaning behind the relationships that exist between the answered questions in order to generate a better understanding of the industry.

I have over 80 respondents across three forums to assess over the next few days. Due to the time required and that I am not conducting an interview based research study, I would prefer not to discuss individual's personal preferences in the forum thread until after my analysis. This is due to be completed over the next few days. If you want to make your opinions known, please fill out the survey before it closes on the 1st May.

Thank you all for your responses, I hope to update you with my findings next week. Unfortunately, I will be unavailable over the next few days for questions.
Forum: Pentax DSLR Discussion 04-29-2011, 08:42 AM  
Masters Degree Survey @ Pentaxforums.com
Posted By cps_goodbuy
Replies: 33
Views: 6,405
I understand your opinion. I would find it interesting to write on photography itself; the history, trends, or in what way digital imaging has changed photography as an artistic medium.

As my course is a business masters that requires a business/industry case study, my survey is tailored for this purpose.
Forum: Pentax DSLR Discussion 04-27-2011, 02:12 AM  
Masters Degree Survey @ Pentaxforums.com
Posted By cps_goodbuy
Replies: 33
Views: 6,405
Thank you everyone for the comments. I'm glad you enjoyed the shopping section!

I'm looking forward to the comparison as I have similar surveys at dpreview.com. I will be updating this thread with the findings after the 1st May.
Forum: Pentax DSLR Discussion 04-26-2011, 05:48 PM  
Masters Degree Survey @ Pentaxforums.com
Posted By cps_goodbuy
Replies: 33
Views: 6,405
A big thank you to everyone who has filled out the survey. I really appreciate the enthusiastic response from the forum.

Looking forward to receiving responses from members who have not seen this thread yet.
Forum: Pentax DSLR Discussion 04-26-2011, 01:46 PM  
Masters Degree Survey @ Pentaxforums.com
Posted By cps_goodbuy
Replies: 33
Views: 6,405
Hello Pentaxians!

I am a long time pentaxforums.com member and looking for some help. Please read below and take part in my survey, any responses would be greatly appreciated. This survey closes 1st May 2011.

I am a Masters student writing a business case study on Pentax (Hoya) and the surrounding camera industry. I would like to include primary research in this study and would appreciate receiving your input via this survey.

The survey comprises of 14 questions where bias of different camera clubs will be taken into account. This survey limits itself to comparing the relationship between Pentax, Nikon, and Canon. Please fill out the form as best as you can, and if there are any areas that you have trouble answering please leave them blank to preserve validity. Thank you very much for your time.


https://spreadsheets.google.com/viewform?hl=en&formkey=dEc0Z0g1M0NIRl9SWGpySm56S3FOQUE6MQ#gid=0
Forum: Pentax Camera and Field Accessories 08-21-2010, 04:19 PM  
Asahi Pentax 49mm Filters
Posted By cps_goodbuy
Replies: 2
Views: 3,752
thought to pm, I have a Ghostless UV mint in case, without the packaging.
Forum: Photographic Technique 08-21-2010, 03:59 PM  
Magazines worth it?
Posted By cps_goodbuy
Replies: 34
Views: 6,232
"Practical Photography" (I think it is a UK magazine) I enjoy. If you have access to it, I suggest buying one or browsing one at least and see if you like it.

It is very much an middle range magazine, that focuses on technique and subject matter. There is a little for beginners and a lot for enthuisiast/pro. I've never been disappointed with it when I get a copy.


Edit: I am of the type, where I prefer to ocassionally browse the magazines and may buy something that appeals. I do not subscribe to any magazine.
Forum: Pentax DSLR Discussion 08-19-2010, 01:43 PM  
Anybody know of a accessory or fix for the K-x to add an autofocus assist light?
Posted By cps_goodbuy
Replies: 29
Views: 6,821
I feel there must be a product out there which is based on the following steps.

Obtain wiring diagram of Pentax brand flash with spot beam light assist.
Reverse engineer spot beam light assist and camera communication.
Reproduce the spot beam light assist and package as a hotshoe mountable module.

Maybe add another shoe on top of module for flash, etc or make a slim line hotshoe module with the spotbeam light assist to the side.

.......we need more electrical engineers in this thread. :lol:

I'm not though :(

It seems to me a good idea anyway
Forum: Sold Items 08-17-2010, 10:24 AM  
For Sale - Sold: FA*24mm/2, FA 50mm/1.7, M 50mm/1.7, DA 50-200mm, AF280T Flash (Worldwide)
Posted By cps_goodbuy
Replies: 15
Views: 5,031
Pm'd, regards
Forum: Pentax SLR Lens Discussion 08-14-2010, 10:15 AM  
Lense Testing: Aperture reliability/accuracy
Posted By cps_goodbuy
Replies: 10
Views: 2,414
Jeff, I think you are missing the point, I am taking about aperture assembly related problems. Doesn't really matter the camera that is stopping it down.
Forum: Pentax SLR Lens Discussion 08-14-2010, 09:54 AM  
Lense Testing: Aperture reliability/accuracy
Posted By cps_goodbuy
Replies: 10
Views: 2,414
Sry, I meant lenses that have the auto/manual switch and the aperture pin.
Forum: Pentax SLR Lens Discussion 08-14-2010, 09:32 AM  
Lense Testing: Aperture reliability/accuracy
Posted By cps_goodbuy
Replies: 10
Views: 2,414
I see what you mean, but if the blades stop down a little bit wide open, then a perfectly round highligh would not be possible. Also, judging by older lense designs that used preset, and from testing a new lense, the blades do not move (stop down) when the camera takes the exposure at wide open aperture.


Change of thought regarding wideopen aperture:

When the camera is instructed to take a photo, I persume that the camera knows the chipped lenses wide open aperture, thus the camera would not stop the lense down at all. But when the camera is instructed to make a depth of field preview, the camera stops it down to the wideopen aperture physically via firmware commands, thus bumping lever and thus the aperture blades.

I will take test photos observing the difference in aperture behaviour between taking normal photos and against preview, as well as changing the custom mode for using the aperture ring as this may change the way in which the camera meters in review mode.

This is all a little hard for me to explain, appologies if it is not clear.

I have found that the (all things being equal) regarding taking the same exposure using different shutter speeds and apertures sizes, that the exposures produced are not equal, thus the following things may be happening:

The aperture assembly is worn, misaligned.
The camera aperture lever is inaccurate.
The cameras shutter curtain is inaccurate.
Or the camera may post process a little bit in camera?!

Meh, will go out and take some real photos :p


I have also observed that when taking a photo wide open the photo is taken but before the mirror returns for the next shot, the aperture is stopped right down to the smallest aperture. Does anyone know why this is? It seems really unnecessary.
Forum: Pentax SLR Lens Discussion 08-14-2010, 09:20 AM  
Lense Testing: Aperture reliability/accuracy
Posted By cps_goodbuy
Replies: 10
Views: 2,414
Thanks for the replies.

I am not speaking of bokeh or other lense characteristics, but rather the mechanics of the aperture mechanism and how this relates to the age or possible misalighnment of the aperture assembly.

I have found that due to the fault of the camera or lense that equal exposure settings, using incremental aperture shots do not produce the same exposure, which in theory, they should do. I have also found out that sometimes when the camera stops down the lense at full aperture (i.e the aperture the lense tells the camera) the aperture blades are hit a little, closing the aperture beyond what is considered a wide open shot (blades close down for the shot) which in a real shooting scenario, whould produce non circular highlighted bokeh.

What do you think of this?
Forum: Pentax SLR Lens Discussion 08-14-2010, 08:21 AM  
Lense Testing: Aperture reliability/accuracy
Posted By cps_goodbuy
Replies: 10
Views: 2,414
I propose the thought that while many people test the optical performance of a lense, including sharpness and out of focus areas, few seem to speak of aperture characteristics.

I wonder if there are any links or articles on the condition of a lenses aperture and testing for this. I feel that the following will influence the final photograph. Most of us know to watch out for misaligned blades and oil however I have come across two similar problems that I would like advice on as I have not been able to find any material on the matter.

The first is that I have found that when Lense A is on Camera A, that if you are in manual mode, you select the widest aperture and then use depth of field preview to stop the lense down, that sometimes while you are looking back through the lense, you can see the blades stopping down slightly, which in my opinion, should not happen. Thus the aperture mechanism may be slightly misalighned in some way?

The other instance is when you make a run of aperture shots of the same continuously lit scene and progress through the aperture range, where either due to the shutter or the aperture reliability, you may recieve different exposures, when in fact you should be taking the same exposure every time? Ie, 1/2 stop increments/decrements via shutter and aperture.

If anyone would like to share their thoughts on this, I would be grateful. Regards
Forum: Pentax SLR Lens Discussion 08-11-2010, 04:51 AM  
which: FA 50mm f1.7 or D-FA 50mm f2.8 Macro
Posted By cps_goodbuy
Replies: 7
Views: 2,111
thanks for the replies guys. I will go for the 50mm 1.7 and see how i go
Forum: Pentax SLR Lens Discussion 08-09-2010, 06:23 PM  
which: FA 50mm f1.7 or D-FA 50mm f2.8 Macro
Posted By cps_goodbuy
Replies: 7
Views: 2,111
I am trying to decide between the two and would like peoples advice on their general use (as in, jack of all trades) hopefully someone has tried both over a period of time and kept one of the two.
Forum: Sold Items 06-14-2010, 11:04 AM  
For Sale - Sold: Like Brand New Pentax-A 50mm f1.4 (Worldwide)
Posted By cps_goodbuy
Replies: 7
Views: 2,831
Lense will be withdrawn Thurs/Fri at the end of this week and placed on ebay.
Forum: Sold Items 06-03-2010, 11:31 AM  
For Sale - Sold: Like Brand New Pentax-A 50mm f1.4 (Worldwide)
Posted By cps_goodbuy
Replies: 7
Views: 2,831
Drop to 170 inc shipping

"please help me pay for my masters degree" :lol:
Forum: Pentax Camera and Field Accessories 06-01-2010, 02:42 AM  
Focusing screen reviews
Posted By cps_goodbuy
Replies: 104
Views: 84,095
Will be testing... shims are dependent on the camera tolerances I think?
Info so far:
Hand Ground Glass
Roughly between 25 and 30 dollars
American Sourced

Edit/Update: does not seem to affect metering.
Will be testing the screen over this weekend, and I have spoken with the manufacturer and may be able to setup a group buy if the screen performs well and there is interest.

Edit:Update: Slightly overexposes I think?
Attaching a photo crop focusing on the tip of the front prong.
Needed to remove a shim and add a plastic shim to solve a front focusing problem with current shim.
Pretty good. Screen represents an accurate depth of field imho

I will contact a member of pentaxforums to write a review.
Forum: Pentax Camera and Field Accessories 05-26-2010, 10:30 AM  
Focusing screen reviews
Posted By cps_goodbuy
Replies: 104
Views: 84,095
Will be testing... shims are dependent on the camera tolerances I think?
Info so far:
Hand Ground Glass
Roughly between 25 and 30 dollars
American Sourced

Edit/Update: does not seem to affect metering.
Will be testing the screen over this weekend, and I have spoken with the manufacturer and may be able to setup a group buy if the screen performs well and there is interest.

Edit:Update: Slightly overexposes I think?
Attaching a photo crop focusing on the tip of the front prong.
Needed to remove a shim and add a plastic shim to solve a front focusing problem with current shim.
Pretty good. Screen represents an accurate depth of field imho

I will contact a member of pentaxforums to write a review.
Forum: Pentax Camera and Field Accessories 05-24-2010, 05:05 PM  
Focusing screen reviews
Posted By cps_goodbuy
Replies: 104
Views: 84,095
I have bought a hand made ground glass plain screen for my k10d online.

I have not tested it other than installing it, but the focus transition is amazingly clear and it is fairly bright.

I feel I should write a review and let others know of this option.
Forum: Pentax DSLR Discussion 05-24-2010, 04:36 PM  
How close is the K20D and K-7 on image quality?
Posted By cps_goodbuy
Replies: 67
Views: 9,302
A: 10mp p&s - depth of field
b: 6mp dslr - really looks like the colours I used to get with my Ist DS
c: 14 mp dslr - dull colours = what I'm getting with the newer dslrs imo (+ there is more fine detail on one of the "buds")
Forum: Pentax SLR Lens Discussion 05-24-2010, 04:22 PM  
Is my FA50mm performing ok?
Posted By cps_goodbuy
Replies: 13
Views: 1,577
I can see a softness that I did not notice with my fa50/1.4 copy. Focus transition imho discounts focus problem. I vote for camera shake.
Forum: Sold Items 05-22-2010, 03:56 AM  
For Sale - Sold: Like Brand New Pentax-A 50mm f1.4 (Worldwide)
Posted By cps_goodbuy
Replies: 7
Views: 2,831
Pm's replied to
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