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06-11-2013, 05:55 PM   #16
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HI Carrrlangas,

Thank you for writing to me. No, I do not have a website.
First, my background treats photography for what is is, a science.
I work only with the facts, so I do not offer any opinions.
I do not find "hear say" or " amateur reviews" useful at all , since
I have been doing precise optical design, optical testing and optical
manufacturing work for over 40 years now. I know the difference between the facts
and the "hype" that is often posted on the Internet and in magazines/books, etc.
Many "posted lens tests" from various test groups are endorsed by the manufacturers.
However, my group has found many mistakes and false publications made because the test procedures
are not up to any rigorous professional standard. My business has very experienced lab personal that have engaged
in the highest level of testing procedures. I work with many agencies that demand the best, and we have
always delivered the services. Over the years, I have worked with major manufacturing companies.

Now, about the Pentax line of lens. Before I can address your very broad based request, I need to have specific
questions answered by you. It is easy for me to recommend the "ED" top of the line Pentax lens at various focal lengths, but your needs
might not require spending several thousand dollars. Often, the results that people obtain with any lens is directly due to what settings
they select for their camera and lens. Putting the camera and lens in "AUTO everything" is not the best start.
Here are some sample questions that I have:
1] Does you interest require fast shutter speeds, or good low light level performance, more or less contrast in the subject, etc. ?
2] Is the definition level most important to you ?
3] Could you operate a lens and camera in manual mode, under any shooting environment ?
4] How are your hand holding skills, steady hands, require a tripod or monopod , etc. ?
5] If you do like a wide range of focal lengths, and not ready to invest in the highest quality fixed focal lens,then getting a zoom lens
with a limited zoom ratio (like 3:1 or 4 :1) is a good start. Keep in mind that the best lens are Not zooms, but there are very good zoom lens .
The above is just a starter list, but it better allows me to address specific questions about what lens is best for your needs.

Best Regards, Mike

06-11-2013, 09:56 PM   #17
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Mike,
With all due respet, I beg to disagree: Photography is an art. It certainly takes advantage of science and technology and understanding at least some of it will help the photographer achieve expression. On the other hand, making a lens is a completely different thing.
Also, I do enjoy "amateur reviews". If you go through the review section of this forum, youŽll see there are lots of them. I never bought a lens based on tests and lab performance but based on sample photos taken with the same camera/ settings I have/use by users very much like me. For example, the DA*16-50 doesnŽt get good numbers in any test IŽve found. But in the field, it really delivers (at list to my eyes).
Your findings are not of surprise, guess this happens on many market areas. What I find interesting is how specialized you and your team must be to detect all of this misinformation.

Regarding the Pentax lens line, sorry for the vague question. I was wonderning, not for me, but if you found, as the Leica 280mm F/4 APO "holy grail", something similar on the Pentax line up.

Best regards,
Francisco
06-11-2013, 10:17 PM   #18
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QuoteOriginally posted by PhotoMike Quote
My personal lens collections tops the collection shown here,
Hi Mike, this collection would be awesome to see, is there any way you can post a few photos of all this gear? It would also be very interesting to see what your testing facility and work environment look like.
06-12-2013, 04:27 AM   #19
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HI Carrrlangas,

There is no doubt that Art, freedom of expression, the preservation of personal memories, documentaries,etc. are are valued factors that are derived from photography.
An individual with a $100 camera and lens can derive as much happiness from the results that his or her setup can deliver. I have seen some excellent postings .
Our forefathers accomplished excellent works using lens and cameras that do not compare to anything made today. Their eye for composition, and patience waiting for the right time
of day to make a capture are a part of that special presence that skilled photographers display.
In my field of work, knowing every aspect of how various sensors (cameras) work along with the lens that are matched to them , allow for an effective system that meets very demanding requirements.
Without lens or cameras, little would advance over time. Photography is a complex science , but most photographers are not compelled to learn the technical parameters to be able produce works that are pleasing to themselves and others.
Photography is a relaxation for many, and fun to do. Buying new or used equipment to use further extends the interest and often curiosity fuels the desire to get more accessories , cameras and lens.
I acknowledge the "personal preference" factors that exist, as this drives many marketplaces.
All of these factors are NOT what drives me to understanding all there is to know about lens, cameras and other instruments used for scientific imaging, survaillance work, forensics, medical research, and many other fields that I am involved with on a weekly basis. I do have much respect for what others obtain with anything that they use, and I recognize and enjoy all forms of photography that I see posted or hanging in galleries.
I also acknowledge the social value of reading and contributing to various groups that have common interests to discuss.
Again, for myself and my colleagues, the time is best spent in understanding the facts about designs and the applications that will best resolve a client's requirements.

Two Pentax lens did very well across a wide range of optical tests are the FA 300mm F/2.8 SMC and the DA 300mm F/4 EDIF. Earlier versions of these lens were also excellent. I have placed several such lens in fixed housings for specific applications.
.
When specifically compared to the Pentax line of lens, the Leica 280mm F/4 APO has the edge in total color correction, meaning across a wider spectral region. This results in a higher contrast and resolution capability.
Many fast "ED" designs still exhibit color fringing or inaccurate color displays until the lens is stopped down from F/2.8 to F/4, The true APO correction corrects beyond the basic target wavelengths that designers use, thus no stop down is required .
There are many "APO" designations placed on lens today, but this is done to promote sales. Some third party lens exhibit more color error as 'APO" designs, than some standard lens using non-exotic glass materials.

Best Regards, Mike

06-12-2013, 04:45 AM   #20
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Hi Christo,

I am planning on posting some images of the various lens that compromise my collections.
Please understand that often some of these lens are used in specific setups to demonstrate
a solutions for a client's needs. They go back and forth from my lab to my home.
I do have a large number of lens that I use by planning outdoor sessions such that I can rotate through
all the focal lengths, etc.
My facility does more than test lens and design lens. We build new prototype optical systems, repair older lens
that have damaged coating or broken elements, etc. Unfortunately, my facility is closed to outsiders because of the status of many
sensitive or classified projects that I undertake.
Here is an image that Betsy, my wife took, with her Point and Shot camera that shows a variety of designs, focal length lens and cameras.
This represents about 3 % of all the lens systems and 10% of the cameras that I have, not including "the one of a kind" specialized systems not sold on the market.

Best Regards, Mike
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DMC-TZ5  Photo 
06-12-2013, 06:32 AM   #21
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QuoteOriginally posted by PhotoMike Quote
Hi Christo,

I am planning on posting some images of the various lens that compromise my collections.
Please understand that often some of these lens are used in specific setups to demonstrate
a solutions for a client's needs. They go back and forth from my lab to my home.
I do have a large number of lens that I use by planning outdoor sessions such that I can rotate through
all the focal lengths, etc.
My facility does more than test lens and design lens. We build new prototype optical systems, repair older lens
that have damaged coating or broken elements, etc. Unfortunately, my facility is closed to outsiders because of the status of many
sensitive or classified projects that I undertake.
Here is an image that Betsy, my wife took, with her Point and Shot camera that shows a variety of designs, focal length lens and cameras.
This represents about 3 % of all the lens systems and 10% of the cameras that I have, not including "the one of a kind" specialized systems not sold on the market.

Best Regards, Mike
WOW! that is really impressive, hope we see some more of the lenses in the future, and also shots taken with the different combinations. I thought I had problems deciding which of my 15 or so lenses to use at any given time....
06-12-2013, 06:36 AM   #22
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WOW !!! Great stuff for being only a part of your collection ... J
06-12-2013, 07:53 AM   #23
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Mike, thanks for your answer. I agree and understand your point of view as an specialist.

Thanks for your comments,
Francisco

06-12-2013, 07:56 AM   #24
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QuoteOriginally posted by altopiet Quote
WOW! that is really impressive, hope we see some more of the lenses in the future, and also shots taken with the different combinations. I thought I had problems deciding which of my 15 or so lenses to use at any given time....
Hi Christo,

I have another image showing about 1/6 of my collection, but among all my images, I have to locate it ! If not, then I will have to setup many lens to re-image them all.
As for using everything, it does take over a year to use some of my cameras and most of the lens. I try to be organized and schedule which lens I am going to use for casual photography.
It is much easier for me when I have a specific task to do, since I can narrow down which cameras and lens would be best to use.
I should mention that Betsy has always supported me in all my endeavors, since many rooms in my home are filled with imaging equipment that she accepts being there.

Best Regards, Mike
06-12-2013, 08:03 AM   #25
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QuoteOriginally posted by Jean Poitiers Quote
WOW !!! Great stuff for being only a part of your collection ... J
Hi Jean,

One evening, Betsy (my wife) and I had a few professional photographers over the the house to chat and have some drinks and snack food.
Their wives were complaining about how many cameras and lens their husbands had, and I felt that I should come to my friends' rescue. So, I brought out
70 lens of all sizes and makes. The conversation quickly focused on Betsy, as they wondered how she was able to live with so many lens.
Her reply was, "you have not seen anything yet" !!!

Best Regards, Mike
06-12-2013, 08:08 AM   #26
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Hi Francisco,

I appreciate your understanding. For myself, some of the best pictures that I took and I cherish each time I view them today, were done prior to my
12th birthday !

Best Regards, Mike
06-12-2013, 05:20 PM   #27
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For all of you that have requested seeing more of my collection examples, I have two unique lens from Pentax.

The small lens on the right is the Pentax screw mount 17mm F/4 Fisheye. It is a surprisingly good little lens, weighing only a few ounces.

I have used this lens for many specialized applications and it has always performed well.

I use this lens with an adapter for any of my Canon DSLR cameras and all of my mirror-less cameras.

The monster to the left is the 40 pound Pentax 6X7 medium format 800mm F/4 telephoto. There are many adapters that allow this lens to connect to most every DSLR camera made.

I have been making adapters for lens for years, so now that the cost has become reasonable, it is cost effective for me to purchase them unless there is a very specialized application.

I use this lens for long distant daylight work and night time astronomical work. It requires a very stable tripod or platform to properly hold this lens in place.

I have scores of tripods ranging from 3 pounds to 150 pounds, so I am covered for this guy.

I obtain very accepted results despite the the claims that this lens is plagued by color until stopped down to F/8 and below. For this example that I hand picked from my optical lab testing, that is not a true statement.

By tuning the lens elements and aligning them , the perfromance became very good at F/4 and excellent by F/5.6 regarding color.

Both lens shown are well built having all manual controls for f-stop and focus. This is just the way I like to see a lens made.

Mike
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06-12-2013, 11:11 PM   #28
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QuoteOriginally posted by PhotoMike Quote
For all of you that have requested seeing more of my collection examples, I have two unique lens from Pentax.

The small lens on the right is the Pentax screw mount 17mm F/4 Fisheye. It is a surprisingly good little lens, weighing only a few ounces.

I have used this lens for many specialized applications and it has always performed well.

I use this lens with an adapter for any of my Canon DSLR cameras and all of my mirror-less cameras.

The monster to the left is the 40 pound Pentax 6X7 medium format 800mm F/4 telephoto. There are many adapters that allow this lens to connect to most every DSLR camera made.

I have been making adapters for lens for years, so now that the cost has become reasonable, it is cost effective for me to purchase them unless there is a very specialized application.

I use this lens for long distant daylight work and night time astronomical work. It requires a very stable tripod or platform to properly hold this lens in place.

I have scores of tripods ranging from 3 pounds to 150 pounds, so I am covered for this guy.

I obtain very accepted results despite the the claims that this lens is plagued by color until stopped down to F/8 and below. For this example that I hand picked from my optical lab testing, that is not a true statement.

By tuning the lens elements and aligning them , the perfromance became very good at F/4 and excellent by F/5.6 regarding color.

Both lens shown are well built having all manual controls for f-stop and focus. This is just the way I like to see a lens made.

Mike
Mike, that big Tak will surely draw some attention, it looks massive!

I would really like to know two things, which I'm sure you'll be able to answer with all the experience you've got in this field:
1. There are two camps on the forums, regarding the use of UV filters. Some say it degrades the final image and is not worth putting on a lens, and others say that it protects the lens coatings, and the impact on the final image is minimal. What do you think of the use of UV filters on lenses?
2. Can you just shortly tell us what you use to clean the lens elements, and camera sensors, and also the methods you use to do it.
06-13-2013, 12:44 AM - 1 Like   #29
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Hi Christo,

Technically, any piece of glass placed over a lens or inside a lens, near the back of the camera is capable of reducing the image quality. I see this daily in lab tests. However, the level of which there is a degradation is minimal for most common applications and many observers would not know what to look for anyway.In a busy seen, a 1 tor 3 percent optical reduction is lost in the scene dynamics. Factors like contrast in very low light level scenes are also effected by using filters. There are applications that can not tolerate such compromise.
I use BW filters, only because our lab tests show a high quality control on many of their offerings. However, when an imaging assignment requires the maximum performance from the lens, then no filter is used or my shop produces custom filters that meet the specifications exactly. Besides the filter material quality, the thickness and flatness used , the optical coating needs to be excellent, too.
On weather extremes, where the scene is compromised by wind, rain, smoke and other debris, I use a BW filter. Under these circumstances, the filter plays a protective role. I also use filters when the humidity quickly changes, causing fogging of the optics. To continue shooting, I remove the filter for a clear view or add another filter in place.

Cleaning is rather straight forward. There are several good kits available that when studying and practicing the producres on a test lens yield very acceptable results.
For myself, I generally do not clean optics that often unless I know the specifics of the type of coating used. Most glass materials that are exposed are very resistant to scratches.
Over the 56 years, I have found that common original Windex cleans glass just fine. The procedure is to start with a particle free surface. A brush or canned air properly used will remove the small particles that can sratch a surface. I use plenty of clean cotton cloths, an always dampen the surface to apply to the lens. I would not place any liquid onto the surface or spray any cleaner onto the surface because it can quickly migrate into the lens assembly.I have had to disassemble many lens that were improperly cleaned. By using many cloths, the microscopic debris is not reapplied to the surface. Pure alcohol is another liquid that is used, too. In the extreme cases like fungus, I often have the lens polished and recoated in my lab.

Best Regards, Mike
06-13-2013, 01:52 AM   #30
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QuoteOriginally posted by PhotoMike Quote
Hi Christo,

Technically, any piece of glass placed over a lens or inside a lens, near the back of the camera is capable of reducing the image quality. I see this daily in lab tests. However, the level of which there is a degradation is minimal for most common applications and many observers would not know what to look for anyway.In a busy seen, a 1 tor 3 percent optical reduction is lost in the scene dynamics. Factors like contrast in very low light level scenes are also effected by using filters. There are applications that can not tolerate such compromise.
I use BW filters, only because our lab tests show a high quality control on many of their offerings. However, when an imaging assignment requires the maximum performance from the lens, then no filter is used or my shop produces custom filters that meet the specifications exactly. Besides the filter material quality, the thickness and flatness used , the optical coating needs to be excellent, too.
On weather extremes, where the scene is compromised by wind, rain, smoke and other debris, I use a BW filter. Under these circumstances, the filter plays a protective role. I also use filters when the humidity quickly changes, causing fogging of the optics. To continue shooting, I remove the filter for a clear view or add another filter in place.

Cleaning is rather straight forward. There are several good kits available that when studying and practicing the producres on a test lens yield very acceptable results.
For myself, I generally do not clean optics that often unless I know the specifics of the type of coating used. Most glass materials that are exposed are very resistant to scratches.
Over the 56 years, I have found that common original Windex cleans glass just fine. The procedure is to start with a particle free surface. A brush or canned air properly used will remove the small particles that can sratch a surface. I use plenty of clean cotton cloths, an always dampen the surface to apply to the lens. I would not place any liquid onto the surface or spray any cleaner onto the surface because it can quickly migrate into the lens assembly.I have had to disassemble many lens that were improperly cleaned. By using many cloths, the microscopic debris is not reapplied to the surface. Pure alcohol is another liquid that is used, too. In the extreme cases like fungus, I often have the lens polished and recoated in my lab.

Best Regards, Mike
Thank you Mike
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