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Messages - Mt Spokane Photography

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4216
Lenses / Re: I'd love a little adivce...
« on: March 06, 2013, 01:09:51 PM »
Older Zeiss Hasselblad lenses adapt very well a 50 or 60mm f/4 might be just the thing.  They miss the mirror by a inch or more.  They are not cheap in the USA, but not super expensive either.  If you cane use 80mm, they are the standard lens and are cheap.
 

 
 

4217
Thanks Roger, and welcome to the forum, I knew I had seen that picture in the blog but couldn't remember, or find, which post it was in. I am glad my memory hasn't failed me completely  :)
And thanks for mentioning it.  I try to read all of Rogers posts, but certainly missed that one.

4218
Lenses / Re: Which 400mm f/2.8
« on: March 06, 2013, 12:38:37 PM »

Of those, you won't find either of the IS versions for less than $3K (and if you see one posted for that sort of price, it's a scam).  You might find one of the older, non-IS versions.  But those are a significant risk - they use electronic manual focus (like the current 85L II), Canon no longer services the non-IS versions of the lens, and AFAIK parts are not available.  Therefore, if the AF fails, you have a club/doorstop/paperweight, since you will not even be able to manually focus the lens.

You might want to consider something like a Sigma 120-300/2.8 OS lens, or a Canon 400/5.6L.
+1
You might find one in your price range, but its very unlikely to be working, they are worth that much for parts.

4219
Lenses / Re: question about extension tubes?
« on: March 06, 2013, 12:33:39 PM »
I'd just pass on contact cleaners.  One of my jobs before I retired was to test them along with lots of other materials hyped by tons of salesmen with wild claims.  They would typically get to a high ranking person at one of our customers, who would then ask our opinion, and we needed a technical response.  The best ones did not cause any harm, but were not really worthwhile either, so we gave the customer the test results and told him that we did not recommend their use.
 
One thing of concern is that cleaners are solvent based, they dissolve grease and oils.  Those contacts in a TC are spring loaded and have lubricant to keep them from sticking.  The lubricant is on the hidden springs and should not be visible, but using a solvent based contact cleaner can dissolve the lubricant and flow it into your lens, mirror, sensor, mirror box, places where it doesn't belong. It can spray out thru piston action when you attach to the lens or to the body and the contact is depressed.
 
I'd recommend avoiding contact cleaners.

4220
PowerShot Cameras / Re: G15 time lapse
« on: March 06, 2013, 12:08:45 PM »
Didn't it come with a manual?  You can download one online if it didn't.
You need to read tthe manual and become familiar with all the controls and capabilities.

4221
EOS Bodies - For Stills / Re: Is this true
« on: March 06, 2013, 12:07:04 PM »
The main advantage my 5D MK III has over my 5D MK II's is the better autofocus and performance in extreme high ISO's over 6400.  I use it at up to ISO 25600 when I have to, and my 5D MK II up to 6400.  Obviously, you don't want to push it to those values unless you have no choice, but in theater photography, its sometimes just necessary.
 
Its a pretty fine distinction, and irrelevant for most users, but, if you need the AF capabilities or the extreme high ISO capabilities, then its the one to get.  It also finally has auto ISO in manual, but no exposure compensation, so full manual might be better in difficult lighting. 
 
 
 

4222
Portrait / Re: First paid photo shoot - DATE: 23 March 2013
« on: March 06, 2013, 11:52:23 AM »
Since you cannot get any additional equipment, as you noted, you can make do with what you have, its just a matter of creatively using it.  Its certainly not helpful to tell you to get more qquipment if you have already said that you can't.
 
Millions of weddings have been shot just fine with lesser equipment.  I have photos that are well over 100 years old, and they look fine, and they used equipment with maybe 1% of the capability you have.  People at the wedding will help you be holding very still if that actually turns out to be necessary..
 
For example, you will not be able to light up a large room or a crowd of 100 people with just the one flash, and I'm not aware of anyway to synchronize the Polaroid and Canon flashes unless you have a slave trigger. 
 
However, you may be able to setup the group outdoors, it depends on the lighting, so try to get them together when the light is best.
 
You sound to me like a pretty savvy person, I'd bet that you will do just fine.

4223
You might consider just getting a USB III drive case  and use a SSD.  The price has really dropped on them, and you can get a fast 250GB Samsung 840 series for about $210, maybe less if on sale, and usb III drive enclosures are not all that expensive.
 
It will blow away any mechanical drive.  http://www.newegg.com/Product/Product.aspx?Item=N82E16820147186
 
Of course, you can get a external thunderbolt SSD, but they are overpriced.

4224
"Do you have a link to Rogers optical bench and colliminator?  as well as the PHD's he has hired to run it?  The last time I saw any information was that he used Imatest like all the other testers."

No. But you need to read him more clearly, he often says things like "A lot of my posts about lens resolution consist largely of showing the MTF 50 numbers from Imatest or our optical bench." and "I grew up in biological and medical research ".


It's a Well's OS-400 system, modified by Wells to take interchangeable mount lenses. We didn't hire any Ph. D.s, but had one come teach us how to use it. As mentioned above, it's not the be-all-end-all but it compliments Imatest nicely. Imatest's greatest shortcoming is it can't measure lenses at infinity and the optical bench does. Imatest does some other things much better than the optical bench, though.

And it's certainly not up to aerospace standards, this is a lower end (albeit still near 6 figures) system, but it does give use some really nice information, particularly regarding astigmatism and frequency response that Imatest just can't provide.

There's a picture and some output from it here: http://www.lensrentals.com/blog/2012/12/another-35mm-lens-for-canon

Thanks Roger, I am impressed!   I've seen the Wells systems online before, but you are the first I've heard of using one that wasn't a large corporation, or a R&D or educational institution.
 
The system we used was partially home made, a 5 X 10 foot slab of 4 inch thick Aluminum plate, that was milled flat and drilled to mount the fixtures.  It also had a expensive shock isolation system to help dampen very low frequency vibrations.  Our techs milled custom fixtures for us as needed for different applications, but we also bought some of the standard components.  We used it for research on military and space applications.  I'd love to have one to play with.

4225
Lenses / Re: question about extension tubes?
« on: March 05, 2013, 10:20:36 PM »
Its not normal to have a excessive amount, I'd also be concerned that more might flow out of the tube in hot weather and cause you to get a cleaning bill for your camera that exceded your savings on the tube.  I'd also check to see if it has a plastic barrel, and join the three togather and flex them to see if a gap opens up.  That is very bad and will ruin a image if they do that.
If you want a third party tube, get a set of Kenko tubes, they are excellent, and you get a whole set from B&H for $190.  http://www.bhphotovideo.com/c/product/375102-REG/Kenko_AEXTUBEDGC_Auto_Extension_Tube_Set.html
 
You might find a used set on Craigslist or ebay as well.
 
I have a set of really old Rokinon Tubes that came with a old film SLR, so they were basically free.  They are plastic, and the lens mount flexes easily if you put much force on them.  This makes them worthless for all but light lenses.  They are ok with my 100L and 135L, but not with a longer or heavier lens.
Since I don't use them except once every couple of years to test something out, they work fine, but for serious photography, I wouldn't bother with them.

4226
Pricewatch Deals / Re: Deals: Canon EOS 5D Mark III & Canon EOS 6D
« on: March 05, 2013, 10:06:09 PM »
Its been pretty well established that the Zeikos battery cannot be recharged with a Canon 6D charger.  They provide a free Zeikos  battery with your 6D that you can't use unless you buy a separate charger? 
 
This is a good way to drive away your customers.

4227
I had the same problem with a 3rd party battery and the 6D charger. It worked a few times and stopped working.. I thought it was because it was a 3rd party battery, so I bought an authentic Canon LP-E6. However, it wouldn't charge using my 6D charger. When I took it back to the store, they charged it using a 3rd party charger and it would charge. So I took it home and tried again with my 6D charger and it worked. This is just a guess, but I'm assuming it won't charge if it is completely flat, but it will if there is a little big of charge in it already.

This is ridiculous.
Actually, its a safety issue, but then to some, safety is ridiculous.
 
Safety requirements
If overheated or overcharged, Li-ion batteries may suffer thermal runaway and cell rupture.[52] In extreme cases this can lead to combustion. Deep discharge may short-circuit the cell, in which case recharging would be unsafe.[citation needed] To reduce these risks, Lithium-ion battery packs contain fail-safe circuitry that shuts down the battery when its voltage is outside the safe range of 3–4.2 V per cell.[35][44] When stored for long periods the small current draw of the protection circuitry itself may drain the battery below its shut down voltage; normal chargers are then ineffective. Many types of lithium-ion cell cannot be charged safely below 0 °C.[53]
Other safety features are required in each cell:[35]
  • Shut-down separator (for overtemperature)
  • Tear-away tab (for internal pressure)
  • Vent (pressure relief)
  • Thermal interrupt (overcurrent/overcharging)
These devices occupy useful space inside the cells, add additional points of failure and irreversibly disable the cell when activated. They are required because the anode produces heat during use, while the cathode may produce oxygen. These devices and improved electrode designs reduce/eliminate the risk of fire or explosion. Further, these features increase costs compared to nickel metal hydride batteries, which require only a hydrogen/oxygen recombination device (preventing damage due to mild overcharging) and a back-up pressure valve.[44]
These safety issues present a problem for large scale application of such cells in Electric Vehicles; A dramatic decrease in the failure rate is necessary.

4228
The lens you pick to use will likely have more of a impact than a focus screen.  A lens designed for manual focus would be the first step.
Then, I'd get one of the viewers with magnifier that fits over the lcd screen and use liveview.  There are also eyepiece magnifiers.
I tried alternate focus screens on my 5D MK II, 1DMK III, and 1D MK IV and decided that they were not accurate enough for me.  Same result with the AF confirmation light.
 
I might also consider magic lantern and focus peaking once the software gets out of the early testing stage.  I'd still need a lcd viewing shade or the like to be able to see the screen in good light.
 

4229
Lenses / Re: What happened to DO?
« on: March 05, 2013, 03:16:50 PM »

 

Just out of curiosity, what makes a DO lens with dispersed particles more effective than the diffraction gratings they use now?

Good question. 
 
Canon has not given up on gratings, here is a patent released in 2012.   http://www.faqs.org/patents/app/20120212821
 
I can only rely on Canon's statement in the patents, but the diffraction varies radially which allows for less CA, but thats assuming the particle dispersion bends the various light rays correctly. 
The gratings are one dimensional and use a glass lens to bend the light.
 
Here is some reading material, there will be a test tomorrow if we can find anyone who understands it well enough to grade the answers :)
 
http://www.faqs.org/patents/app/20110317276

4230
Accurate enough for what? They could well be derived from completely different methods, so the one thing you can't do is accurately compare between manufacturers. You also can't compare different focal lengths! So whilst manufacturer presented MTF graphs might be "accurate enough", I was just adding a cautionary note to those who were comparing Nikon figures to Canon figures. Just like MPG estimates, they have very limited value and shouldn't be a serious basis for a purchase.

Lensrentals now has the equipment to measure lens resolution without being mounted (to a camera as we know it) so they can, at least, give genuine comparisons for lenses across manufacturers.
MTF is definitely not the final word, but its a starting point, and a lens is not going to be better than the manufacturers posted MTF. The values that the camera manufacturers are good enough precisely because of this, there is no use being accurate to 5 or 10%% because it is only part of the story.
 
Do you have a link to Rogers optical bench and colliminator?  as well as the PHD's he has hired to run it?  The last time I saw any information was that he used Imatest like all the other testers.
 
Measuring the MTF of a lens with a optical bench, slit illuminator,  not only takes 500K of equipment, but also needs some very skilled technicians to intrepret the results.  I had all of those in my lab at a large aerospace company, and it was a big investment assembled over several years of R&D budget.  We had several lab techs and engineers / scientists using it.  Its not something easily done. 
 
Somehow, I wonder if Roger has acquired this ability, or even why he would want to, since Imatest is plenty good for what he does.   But please give me a link and impress me.

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