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Messages - LowBloodSugar

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1
Third Party Manufacturers / Re: Sigma 135mm f/2 DG OS Art Coming? [CR1]
« on: December 17, 2013, 08:58:23 PM »
Its strange that canon doesn't have more IS lenses.  100mm 2.8L IS Macro is the only macro IS prime canon has near that range.  The one drawback of that lens is that manual focus is twitchy at longer distances.  I am hoping for a non-macro IS prime in the 90-135 range.  Perferably canon.  This is an enticing rumor

2
EOS Bodies / Re: Why are DSLRs so Big?
« on: November 04, 2013, 08:06:47 PM »
The size and shape of canon's DSLRs are a consequence of the 35mm SLRs.   Early DSLRs still had the motors and gears for advancing film.

They have to be as thick as they are to allow for the amount of distance between the sensor and the lens mount.  Plus there is a mirror/prisim and a grid of focus sensors.  Because of these limitations there was no miniaturization.

NOW that there is fast dual cmos focusing, that paves the way for a smaller mirrorless autofocus interchangeable lens camera that could be on par with canon's flagship cameras (5dm3/1DX).

3
Does anyone know of a source for cheap but still optical quality polarizing sheets?  I bought some from rosco and they were really only good enough for lights.  It really blurred the image when i used it with a lee filter holder.  I ended up getting a lens BW polarizer and was very happy.

4
Lenses / Re: What lens for panoramic tour + what software?
« on: August 20, 2013, 04:47:10 AM »
I have done this in the past.

My lens of choice is the canon 8-15 F4L. I have tried a few other fisheyes and it is superior to the cheap prime fisheyes on the market (samyamang, sunex, etc). You can use any lens for a 360 but really you want to stream line the process so that means 8mm on full frame


It works on both apc and full frame. Obviously full frame is easier.  I get great 360x180 shots hand held even in low light. But I have a cyborg brain.

For serious work I use a nodal ninja head on a tripod.

On small LDR tours:
 I import to Lightroom and preprocess then export to ptgui pro.

For large tours:
Auto pano is better, but please note that it uses Time to determine what photos belong to what pano. And it will get tripped up if you take a long time for one pano and do another one quickly.

You should really understand and experience how that works before shooting a long tour.

Disclosure: I have a business relation with canon.


5
Lighting / Re: photographing paintings that have thick paint
« on: July 03, 2013, 03:22:30 PM »
In a controlled environment where you are shooting art, why not use the speed of tethering via USB?
Eye-Fi chugs along OK with small JPEG's, but RAW transfer can only be described as glacial.
-PW

The eye-fi wasn't that bad.  I had it directly connected and set to not upload to internet services.  I was cropping the previous photos as the new ones were coming through.  Not bad, but I will try USB next time.  I imagine that the large screen live view will help.

Also by the way, the 100 2.8L IS macro focus ring is is specified at 157 degrees from 1:1 to infinity.  Which seems great, but it is geared so that at macro distances the you have better control of focus and at longer distances its super touchy...  I think next time I will try a no-macro like 100mm f2 or 135L which have more "focus throw" at the distances i would be working at.

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Lighting / Re: photographing paintings that have thick paint
« on: July 02, 2013, 01:39:33 AM »
It was actually a problem on some of darkest paintings and some that had interesting frames.  I ended up shooting a x-polarized and a second with partial polarization for the problematic ones and blending the two.  Probably the most important thing i had was an eye-fi card sending the the raw photos to my laptop.  I had it set up so that the photos would automatically get imported into light-room and have the color profile applied on import.  I was able to catch whenever i messed up and needed an second photo very quickly.

7
EOS Bodies / Re: Canon Dual Pixel Liveview Autofocus
« on: July 02, 2013, 01:32:36 AM »
They have all the pieces of the formula now!  Its only a matter of time until canon makes a proper mirror-less EF compatible camera!

8
Lighting / Re: photographing paintings that have thick paint
« on: June 29, 2013, 06:06:56 PM »
Back from having done the shoot using a cross-polarizing setup. 

I ended up renting the canon 100mm 2.8L IS macro and using 50mm 1.8 as a backup when I couldn't fit everything in the frame.  I tried to use the rosco brand polarizing film for the lens and it just was too blurry(produced perceptible glare).  I switched to getting an fancy b&h circular polarizer and that was much better.

I used two youngou flashes at full power with rosco brand polarizers at 45 triggered by an on camera set at lowest power (with polarizer).  Studio flashes would have been better, but this was still good.  The polarizers started to loose effectiveness part-way through the shoot and had to be replaced.  Full power flashes damaged them.  I made a spacer so they would be a little cooler and they didn't need replacement after that.

Most of the large paintings were taken on the wall with a black backdrop gaffered taped to the wall.   

Keeping the camera lined up squarely with the art was actually very tedious and I am looking for ideas on how to do it better.  I wish the world had a "snap to grid" checkbox!

Small paintings were taken on a camera copy-table.  That was easier to use than the wall because the pictures stayed centered and square.

Minimal post processing needed other than XRite color checker passport calibration workflow.   I was unsure on which controls to use for brightening photos some of the darker photos.  With the artist we agreed on what the proper exposure should be for some of the darker images, but was very happy with all of the photos.

Thanks again pwp.

Clement

9
Thanks for sharing!  Seems like a solid workflow...

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Lighting / Re: photographing paintings that have thick paint
« on: April 29, 2013, 06:55:43 PM »
Thank you for your thoughtful response.  I am excited to try your suggestions.

My shots from before were coming in with significant glare.   The polarization filter that you suggest will minimize that.  I was using an umbrella diffuser to help get even illumination, but that will have to be removed because the umbrella diffuser will "mix up" the polarized light from the flashes and turn it into unpolarized light.

I have been using the "X-Rite color Checker Passport" and that is producing great results and it is straightforward to use (as long as you are operating in a controlled laboratory like manner).

Thanks again.


I shoot a lot of art for a number of clients, galleries & artists. If the works can be described as having dark, glossy, heavy impasto surfaces, I quote at least twice as much as I would for completely flat work. It's a bitch.

For works up to a couple of meters on the long side, I use two Einsteins with the standard 8 inch reflector, with polarizing gels on the lights. The lights are set back 3-5 meters at 45 degrees to the work, just like on a copy-stand. I also have a polarizing filter on the lens. Shoot tethered so you can have a very clear look at what you're doing. Even a very small adjustment to the light alters the result. It's very important that both lights and modifiers are 100% identical. Make sure you can work in a BIG space.

If there are multiple works, set up an easel and bring the works to your setup. If you move your setup for each work it will take you weeks to do what you can do in a day.

If there are still blown highlights/catchlights in the dark impasto areas, they can be fixed in post in a variety of ways. On an adjustment layer you can hit "dust & scratches" and/or "despeckle" and brush in the trouble spots through a layer mask. Or you can use the color range tool to select the blown areas, feather a tiny bit and literally paint them in. Or a combination of all these things. Remember to just reduce the blown areas till it looks good, not kill them completely or you take away the fact that it is a heavy impasto work. It's a tightrope.

Color? Get yourself an X-Rite color Checker Passport and use as directed. Trust the numbers more than what you perceive. If the works are framed, watch out for shadows thrown on the work by a deep frame.

Dark, glossy, heavy impasto paintings are the hardest of all. Good luck. If the work is important, and you feel it is beyond you at your current skill level, it may be best to pass on the job, skill up and start pitching to prospective clients again later. It's an area that looks simple but is full of traps for the unwary and inexperienced.

-PW

11
Lighting / photographing paintings that have thick paint
« on: April 21, 2013, 11:14:06 PM »
I just moved this thread, because i had previously posted it in the wrong forum.

I am trying to build the ultimate setup for photographing a collection of art.  Mostly large oil paintings (3feet x 4feet +/-)  with significant impasto (thickly applied paint that has depth and 3D shape).  There is also hand painted dinner and dessert plates that are glossy.

After much research and trail runs my list of goals are as follows:

1) Maximize sharpness
2) Maximize contrast
3) Maximize resolution
4) minimize vignetting
5) minimize distortion
6) minimize chromatic aberration
7) minimize out of focus fringing
8 ) minimize camera shake AND camera vibration
9) minimize glare,
10) reproduce accurate color
11) maximize uniformity

unknowns:
what is the best angles to put lights so that the paintings self shadowing looks the best (45, 45 copy table style is often recomended, but i think it produces unnatural looking shadows on the paint structure)
should lights be large or small ( soft shadows or sharp shadows )


so far this is the setup that I am thinking will produce the best results:

CAMERA: Canon 5DMK3 (currently owned) on a sturdy tripod or copy table
Set to mirror lockup and shooting raw

Lens:  I have been using a Canon 50mm MK2 1.8 lens with great results but I am considering upgrading to   100mm 2.8L macro IS, or 100mm 2.8 macro, or 135mm 2.8L.  Obviously in this situation a "flat field" prime lens will produce the best results.  I am expecting something like a 5.6 or so aperture will be the best.

Color treatment: xrite color checker passport <- for color calibration (highly recommended).  Use color calibration to get color correct, and don't do any other tweaks.

LIGHTING:
Currently this is the most nagging question for me.  i am using lowelpro continuous lights which have a high color rendering index.  I am experimenting with one or two set with a diffusion umbrella at about 45 degrees.  And one or two lights without diffusion to produce sharper soft shadowing.  But im worried that the shutter speed is just too long and also it produces uneven lighting and camera vibration is still present even on a tripod.  I am thinking that possibly i could switch to using strobes witch would reduce vibration.   I am also considering the wesscot grid flash modifier for creating highly directional and uniform lighting or moving the strobes very far away and not using any modifiers.

ALSO, i am wondering if i should be shooting in a black room or white room.

I am also doing what I can to reduce flare by looking at the histogram and goboing the lights just to make sure i am not getting any issues from off frame lights spilling into the lens.

Do any of the canon rumor members have any advice or experience to share for photographing paintings that have thick paint?

12
Pricewatch Deals / Re: EF 24-105 f/4L IS for $770 Shipped
« on: April 21, 2013, 09:04:17 PM »
people in a forum were complaining this was a bad deal because you can fine then on craigslist and eBay and Fred Miranda for less.   but I don't see spending and extra 500  on the kit  to sell it for six hundred.

Yeah, exactly.  It amazing how financially liquid L lenses are.  I traded my t3i + EF 24-105 F4L IS + EFS 17-55 2.8  IS for a year of maid service on two condos!

13
Lenses / Re: Why some lens says "macro"?
« on: March 23, 2013, 01:08:38 AM »
The 8-15mm fisheye zoom achieves 0.39x mag!

WARNING:  Objects in fisheye are closer than they appear.

Be very careful.

14
Lenses / Re: IS or no IS?
« on: February 07, 2013, 07:54:11 PM »
I am in the market for an IS lens for indoor photo and video work.  IS is a must for me.

I am considering:
Canon 24-105 f/4L IS
Tamron 24-70 2.8 VC
Canon 35 F2 IS

I just rented the Tamron 24-70 IS from lens rentals, and liked it.  Its a bit big.  IS worked well, but its not a magic.  You still have to hold still when hand holding the camera.

I had the efs 17-55 2.8 IS and it was really amazing lens, but incompatible with full frame.

Does anyone know of any websites that show comparison of IS on various lenses for video?  Are some IS lenses able to absorb more motion than others?


15
Lenses / Re: Help with 360º Panoramas
« on: January 17, 2013, 05:39:15 AM »
Hi,
I want to take 360º panoramas with my 5D. Can I use the sigma 15mm rectangular fisheye or will I need a circular fisheye?
If it can be done with the sigma 15mm rectangular fisheye, how many shots wilI I need?

Thanks.

Hello,
You can make a 360 pano with any lens, but the wider it is the easier.  I am guessing you are talking about a 15mm fisheye.

The sigma 15mm produces a image circle centered on the image plane and the edges at the left and right on a full frame sensor.  The top and bottom are cut off.  To create a 360, the easiest is the rotate the camera into portrait mode, and take 6 images in a circle.    If you have a crop sensor camera, the image will produce about a 180 fov across the diagonal, so it will take more photo to cover the full visual field.

I decided on the Canon 8-15mm F/4 zoom for my 360 Panos, which by the way is may favorite lens.

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