March 01, 2015, 02:12:32 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - noisejammer

Pages: [1] 2 3 ... 12
1
Lenses / Re: Schneider 28mm Tilt Shift
« on: February 18, 2015, 09:47:33 PM »
At that price, you'd be well advised to read Lloyd Chambers' review. He was singularly unimpressed. To quote him "By any metric this performance disappoints." Full disclosure - you will need a subscription. The review is in the DAP section.

If you're interested in alternative TS lenses, take a look at the Hartblei SuperRotator range. I have one of these and it's superb.

2
Canon General / Re: Decline in DSLR sales explained
« on: February 16, 2015, 08:49:04 PM »
I think PhotographyFirst nailed it ... phones offer quite acceptable image quality for almost everyone.

Sure, you can offer a dumbed down interface on a DSLR (but the green box is there already.)  The truth is that some people - perhaps most people - are unwilling to learn new skills. I know a wildlife photographer who owns a 300/2.8, 600/4 and a couple of 1D3s bodies... and who has no desire to ever take the camera out of P (for "professional") mode. Until I showed her Snapseed, even cropping was too much hassle...

I submit that falling sales are nothing to do with ease of use - potential customers already have a camera that does everything they want... and it came "free" with their phone. They may even have a DSLR that disappointed them because they thought "Better camera = better images," a fiction that every manufacturer lives by. Although their images may improve with effort, this is not disclosed up front. Since they're loathe to blame their own incompetence, they become former customers who view this is misleading advertising.

I'll end with this -
When I started photography 40-odd years ago, an SLR was a treasured possession - you might expect it to last fifteen years or more. Few people had first class cameras (as a measure, I was the only chap in my army regiment.) That was considered "normal." Is the expectation of market thrashing realistic?

3
I just like to have only the eyes in focus in the face, so subject-background-seperation will not help here. From Zeiss I only own the 135 f/2, and I wish to get it tag sharp at least 90% of the time at f/2 without zooming the live view on the camera.
You can easily calculate the distance to the subject by using
D = F * H / h where F = focal length (in your case 135mm), H = subject height or width ( I'll guess 450 mm width) and h = sensor height or width (if you're in portrait orientation it would be 24 mm width. From this, I get your subject distance is going to be about 2500 mm.

Now go to www.dofmaster.com and do your own calculations. I got that the total DoF will be 3.9 cm split nearly equally between front and back. That assumes the circle of confusion is 0.03 mm. If you want the image to be a fair reflection of your lens' capabilities, you can set the CoC at 0.015 mm and you'll find the total depth of field is 1,9 cm. That's 1 cm in front and 1 cm behind. If you're human, you will sway by several mm (as will your model - even if he / she is trying to stand absolutely still.

The result is that even if your focus is perfect, you might only get 50% of your images sharp but you should get about 25% sharp. This is why it's far smarter to stop down the lens a little and make sure you nail every image.

It's easy to test this - focus on something that's difficult to see then shoot off several images. You can even use this to estimate how much you sway which should inform how fast an aperture you should be using.

4
Do you consider the loupe to be good enough to focus on the eyes for a close-up (from top head to including shoulders) portrait at f/2 or do you get better results when you do zoom in (the camera button) on liveview?
Head and shoulders at what focal length? I'll guess 85mm / 1 m.

The worlds great optimist-sage, DofMaster, says at f/2 is 85 mm lens, 1 m -> 2cm ... that's assuming the CoC is 30 microns (which is quite crappy.) You would do better to try for CoC around 15 microns which means the DoF is 1 cm.

To achieve this, you and your subject have to stand still so that neither of you sways by more than 5 mm. I wish you luck - you will need it.

It's not for nothing that pro's shoot portraits at f/4.  If you want more bokeh, separate the subject from the background or use a green screen.

5
Thanx  ;D
Just some small questions:
-How easy is it to see the composition (e.g. the entire screen) with the loupe attached? Can you see the entire screen only by 'hovering' with your eye over the loupe or can you still see your entire screen at once?
I can see the entire screen without having to move my eyeball. Of course, you have to use magnified live view if you really want to nail focus. I frame the image, pick my focus area, focus, zoom out then trip the shutter.
Quote
-What is the purpose of this gorilla plate?
I think it interfaces with the other video-related things Zacuto makes. It may allow some of the parts to glom onto the camera. As I said, it's useless for stills - use the Z-FRM or Z-FRM32.
Quote
-The 2.5x and 3x are different magnifications I assume?
Yes (I assume) - I've not used the 2.5x so I can only go by what's on the Zacuto site.
Quote
I see in some youtube videos that there are some kind of spacers that come with the package to increase the distance between loupe and screen and thus the magnification. These spacers are not related to the 2.5x and 3x versions?
No - the spacers allow for greater dioptre correction. I have never used mine.

NJ

6
I tried the Hoodman before trying a Zacuto. I found the Zacuto to be far, far better.

Zacuto makes three Z-Finder models, the Junior, Pro 2.5x and Pro 3x. I haven't tried the Junior so I can't speak to that. Between the Pro versions, my choice was based on dioptre adjustment. If memory serves, the 2.5x version offered lower magnification but was suited to near-sighted shooters. I'm not near sighted so I chose the 3x version.

The Gorilla plate that comes packaged with some Z-Finders is a waste of space. If you can save some cash by not buying it, I recommend you do.

7
I'll post a dissenting opinion.

I've purchased just about every screen available for the 5D2. I have tried precision matte screens, split focus, the original, microprism and a few others. The prices varied from $15 to $200.

The short version is that none allowed my to achieve critical focus with my Zeiss ZE lenses.

I then tried a Zacuto Z-finder Pro loupe and mounted it to the lcd on a clip-on frame (pn Z-FRM or Z-FRM32 depending on your camera.) I can nail critical focus almost every time. Yes, it's a little unwieldy but the camera is pressed against your eye and it's stable. The second issue is that this goes through batteries, so you need a few in your pocket. It does however work.

8
Post Processing / Re: Is Coma Fixable in Post for Astrophotography?
« on: January 21, 2015, 10:31:24 AM »
Does the point spread function vary across the image? Or does the function completely describe the aberrations across the lens?
Coma is a radial aberration so the psf varies radially. Richardson-Lucy deconvolution was developed to allow correction for this. Since stars are essentially point sources, it's quite easy to determine the psf over the entire field.
If memory serves, it was originally a software kludge that allowed the space telescope to be used while COSTAR was being developed.

9
Post Processing / Re: Is Coma Fixable in Post for Astrophotography?
« on: January 20, 2015, 10:56:42 PM »
Yes, but with some difficulty. I suggest you look at the Richardson-Lucy transform. You will find implementations in MaxIm and AstroArt - perhaps in others too.

10
I use a this ... http://www.thinktankphoto.com/products/streetwalker-harddrive-backpack.aspx . It's more than sufficient for my 1D4 + 5D2, 70-200/2.8, several smaller lenses and a decent sized laptop. You can remove some (or all) of the compartments as needed and there's a waterproof cover that keeps things reasonably dry.

If you're worried that the airline may gripe about the weight of your bag, wear a jacket with multiple pockets. If they get overly fussy, hang your camera around your neck and unload the bag until they let you keep it. Once you're on board the plane, you can reload the bag.

I also subscribe to the idea of taking a sling bag along for my camera except that mine travels empty in my checked luggage.

11
A choice of two, take images and stitch like crazy...

1. Hartblei 80/2.8 super rotator
2. Zeiss ZE or ZF.2 50/2 Makro

Both are superbly sharp and easily out-resolve my 5D2. The Hartblei also offers tilt-shift capability.

12
Lenses / Re: Comparison: Yongnuo 50mm f/1.8 vs Canon 50mm f/1.8
« on: December 29, 2014, 12:59:49 PM »
<p>PetaPixel has posted a comparison between the Canon EF 50mm f/1.8 and the obvious clone the Yongnuo 50mm f/1.8. </p>

These lenses have different optical designs (from the comparison on Petapixel, the YN is clearly better), they have different irises (the YN is better) and they have different price points (again, the YN is better.) Apart from both fitting on the EF mount, I don't see there's any cloning involved at all.

13
Canon General / Re: RTFM. Do you?
« on: December 10, 2014, 05:05:17 PM »
Those who play first, curse later - have you ever tried to set up a 1-series without rtfm... :D

14
Third Party Manufacturers / Re: Most ridiculous camera ever?
« on: October 31, 2014, 05:53:32 PM »
...and people are scared of Magic Lantern brikking their cameras...

Man, I thought the Df was hideous but this really wins the 2013 fugly prize. :)

15
Canon General / Re: seeimpossible.usa.canon.com?
« on: October 07, 2014, 09:16:55 PM »
Oh give me a break! You really can't think that "youtube" comments are representative of anything other than the opinions of the handful of individuals who comment – who, for that matter, could very well be Sony employees for all you know.
At least one of the comments did not come from a Sony employee.
In any case, why would Sony employees see value in getting Canon to make better products?

Pages: [1] 2 3 ... 12