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Messages - K-amps

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1441
EOS Bodies / Re: Ball pitching speed / Shutter speed accuracy experiment
« on: September 21, 2011, 05:06:38 PM »
Hi, K,

I am trying to estimate the velocity of a pitcher (the radar gun I have does not seem to be not accurate) using a framed capture at 1/60th of a second.

Does the "scan" aspect of the FP shutter introduce any complication into your process? Perhaps with a shutter speed of 1/60 s it would not be a factor.

Is the travel of the ball parallel to the focal plane (or at a consistent angle to it)?

Interesting project.

Best regards,

Doug

Doug: thanks for reading through my "blog" there.

I am afraid I have to plead ignorance to the ""scan" aspect of the FP shutter" question. This was a series of stills, the capture should have lasted 1/60th of a second in my mind.

The angles and other aspects of the ball line were far from perfect, for Pitcher 1, the 1d2 was handheld and there is vertical blurring, but it has little impact (little) on the horizontal trajectory. A +/- 5% margin of error is very much a given;  the way i did the experiment, but I am getting an over 10% difference from expected result.

See the attached pictures and see what I mean. The blur of the ball is clearly different lengths. Pitcher #2 should be faster or equal to Pitcher #1.

1442
Canon EF Prime Lenses / Re: Canon EF 180mm f/3.5 L Macro USM
« on: September 21, 2011, 04:08:18 PM »
100mm is a bit short for insect shots... either I scare them or they scare me at 2 feet.

now if I can get a nice cheap, and sharp used 180mm :)

Depends on the insect.  I've gotten some nice insect shots with the MP-E 65mm f/2.8 1-5x, and the working distance on that lens is between 1.6-4 inches, depending on magnification (and since you can't go below 1x due to the lack of infinity focus, 4" is the longest working distance possible!).

I have seen a 180mm f/3.5L Macro pop up on my local Craigslist in the $950-1000 range a few times, as recently as a month ago.

Were you the guy that shared a pic of the pink flower / trident stamen with the MPE-65? It was gorgeous. What do you use for illumination?

1443
PowerShot Cameras / Re: Sensor Pixel Density
« on: September 21, 2011, 02:43:15 PM »
Q1: I would think no, because native pixels are sharper (more clarity) than interpolated pixels. This is assuming your Camera uses the whole sensor and not a crop at 10mp. I am saying this because if you set your monitor to a smaller resolution than it’s native resolution, it is interpolating pixels and it gets quite blurry. At magnification levels that are square roots or similar proportional numbers, the perceived sharpness is better e.g. 50% magnification looks better than 66% magnification on screen. So there is a relationship between the nativity vs. interpolation of the pixels. So I think the answer to this question might be a “No”

Q2) Might better to use a good software to reduce it. For example bicubic scaling is better for reductions as it naturally sharpens, and Bilinear is better for enlargements as it smoothens jaggies. Fractals are even better at enlarging. My guess is specialized software for resizing should out-do the in camera resizing.

Here's some info on the reduction/expansion algorithms: http://www.codinghorror.com/blog/2007/07/better-image-resizing.html

1444
EOS Bodies / Ball pitching speed / Shutter speed accuracy experiment
« on: September 21, 2011, 02:27:53 PM »
I am trying to estimate the velocity of a pitcher (the radar gun I have does not seem to be not accurate) using a framed capture at 1/60th of a second.

I set a 1d2 at 1/60th sec capture then measured the trail of the ball and (how much it moved in 1/60th of a second); did some on screen measurements; ran some calculations; to get at an expected speed of 90.12mph.

I think this is very close to what I thought his speed would be, so I was confident in the modelling.

This was a cricket pitch, but lets use baseball analogy if it helps.

We have another pitcher that we think might be a bit faster or at least the same than Pitcher #1.

This time I set a 5Dclassic (that I had on me at the time) with the similar (though not same) framing and 1/60th frame capture. I figured as long as I can get a ratio of the ball trail vs the diameter of the ball, I’d end up with a constant that could be uses to compare the two captures and calculate the speeds. We also have a third pitcher who we feel is a bit slower than #1 and #2 that I framed the second time as well.

To summarize:

Pitcher #1 = 1d2 1/60 sec
Pitcher #2 = 5D 1/60 sec
Pitcher #3 = 5D 1/60 sec

For that batters (batsmen) who have faced these 3 guys feel Pitcher 1 & 2 and neck and neck at around 90mph, while pitcher 3, is about 7-8%  slower.

Results:

Pitcher 1 = 90mph (1d2)
Pitcher 2 = 77mph (5d)
Pitcher 3 = 67mph (5d)

While the speed differential between pitcher 2 & 3 is absolute since the test and the conditions are identical (even the trail in the photo bears out a 14% difference between them) what I cannot believe is that Pitcher 2, is only 77mph (though he seems very close or faster than pitcher 1).

I may not be able to assemble these guys together for a retake with the same equipment so here is my question:

When the 1d2 takes a picture at 1/60th of a second, how accurate is that? Same for the 5D.

Based on this, it seems to me that there is a 15% difference between the 2 bodies. Should I trust one or the other? Are shutter speeds that accurate?

1445
Canon EF Zoom Lenses / Re: Canon EF 70-300 f/4-5.6L IS
« on: September 21, 2011, 01:32:26 PM »
Hi K-amps,
I use CS5, and I still have a LOT to learn. Generally I select what I do not want to blur, refine the edge and then invert the selection to apply the blur. I use the quick selection tool and then use the lasso for fine-tuning.


Same here. Did you use gaussian or lens blur?

1446
Canon EF Prime Lenses / Re: Canon EF 180mm f/3.5 L Macro USM
« on: September 21, 2011, 01:16:25 PM »
@K-amps

I don't know what your definition of nice or cheap is, but there is a 180L on B&H right now for $1250.

Thats not too bad, what I was thinking is Near MINT used for $950  (good copy... if it matters)

1447
EOS Bodies / Re: Nikon unveils V1 and J1 Mirrorless Cameras
« on: September 21, 2011, 11:30:26 AM »
.......   but f/2.8 on their CX sensor is equivalent to f/7.6 on FF...not very impressive....


I never knew there was a correlation as direct as that. So if I have a 24-105 f4, is that like f6.4 on a APS-C sensor; or do we need to consider other factors too.

Just learning here... cause then my f4 lens on a 5D is not too bad compared to his 70-200 f2.8 II on his 7D (f4.48 equivalent) or should I consider other factors too.

Basically, yes.  But to be clear, the crop factor applies to aperture in terms of depth of field for equivalent subject framing...so, f/2.8 on APS-C gives you the same depth of field that you'd get at f/4.5 on FF, for the same subject framing.  The reason is distance - the crop factor means a narrower angle of view, so to match the framing you need to be further away with APS-C, and that extra distance means a deeper DoF. 

Many people don't realize this.  A great example is people who state they won't upgrade to FF until the 24-70mm has IS, because they want a FF equivalent of the very nice EF-S 17-55mm f/2.8 IS.  What they don't realize is that such an equivalent exists...and is actually better spec'd - the actual FF equivalent of the 17-55mm is a 27-88mm f/4.5, so the 24-105mm is wider, longer, faster, and still has IS plus on the 5DII it will out resolve any APS-C sensor.

The effect of crop factor on aperture does not apply to exposure, though with the better ISO performance of a FF sensor, you can bump up the ISO to compensate for the loss of a 1.3-stops of shutter speed.

 I was thinking the exposure, but this clears it, thanks neuro and Liberace

1448
Canon EF Prime Lenses / Re: Canon EF 180mm f/3.5 L Macro USM
« on: September 21, 2011, 11:08:28 AM »
I also owned 100L, then got myself a 180L, and sold the 100L right away.

IS is surely nice to have, and i'm sure they will release the 180L IS version eventually, but at this point I consider 180 so much more my type of lens due to a special bokeh (looks somewhat old-school to me), reach that you need for macro work (insects tend to escape when approached with shorter focal lengths), and it can also serve as a long portrait lens, more so than 100L due to the fact that there are many other alternatives in that range (85L, 100/2, 135L etc).

I am glad I am not the only one that has thought of ditching the 100L for the non-IS 180mm... Fully agree, 100mm is a bit short for insect shots... either I scare them or they scare me at 2 feet.

now if I can get a nice cheap, and sharp used 180mm :)

1449
EOS Bodies / Re: Nikon unveils V1 and J1 Mirrorless Cameras
« on: September 21, 2011, 10:30:21 AM »
.......   but f/2.8 on their CX sensor is equivalent to f/7.6 on FF...not very impressive....


I never knew there was a correlation as direct as that. So if I have a 24-105 f4, is that like f6.4 on a APS-C sensor; or do we need to consider other factors too.

Just learning here... cause then my f4 lens on a 5D is not too bad compared to his 70-200 f2.8 II on his 7D (f4.48 equivalent ?) or should other factors dwarf this correlation?

1450
EOS Bodies / Re: Your wishlist for your next body...
« on: September 20, 2011, 04:13:02 PM »
I would like Canon would add a new focusing mode that would automatically focus at the hyperfocal distance. Thinking about it, the only thing the camera needs to calculate the distance is the focal distance (it knows it), the aperture (it knows it) and the circle of confussion diameter (it's a constant value for each camera). Then the camera would focus the len at that distance. It would be great for night, where there are great difficulties to focus and landscape photography.

In this mode the camera would ignore the focus points and would focus at the hyperfocal distance.

Wouldn't it be great?

Do you want it Pro AF (not 7D like)?  ;D

1451
Canon EF Prime Lenses / Re: Canon EF 180mm f/3.5 L Macro USM
« on: September 20, 2011, 01:54:32 PM »
A question about the 180L. I frequent the used camera gear sites frequently (B&H for example) and the lens I see most for sale in the used section is the 180L. Anyone have any thoughts as to why this might be?

$1200-1400 is a lot of money to be tied up in a specialty lens if one is not doing macro all the time.

1452
Canon EF Prime Lenses / Re: Canon EF 180mm f/3.5 L Macro USM
« on: September 20, 2011, 01:51:34 PM »
I have used it, but honestly, I think the 180mm is sharper, and the 100L doesn't have enough of an increase in image quality from the regular 100mm 2.8 USM to warrant an upgrade (my opinion only).  Sure the IS would be nice, but I've done without for a while now and will probably continue to do so.  Plus, if you plan on using one of Canon's macro flashes with the 100L, you'll have to get the 67c adapter where as the flashes fit right onto the 100mm 2.8 USM. Both of those are in a totally different league than the 180 though due to the major difference in focal length, etc.

+1

I owned the regular 100mm Macro and the L (sold both) and thought the regular was sharper. I salivate at the thought of getting the 180mm though, but the price is a bit steep. The bokeh on it is just gorgeous.

1453
Canon General / Re: 70-200 2.8L IS 11 or 70-300 4-5.6L IS?
« on: September 19, 2011, 09:00:30 PM »
Hello:

Whoever owns the 70-200 f2.8 II loves it. The speed of the lens is a big advantage. I got one, returned it and got the 70-300 since I wanted a bit more zoom. The 70-300 might be slower but I do not usually shoot indoors dimly

The 70-300 IS is as sharp if not sharper than the 70-200f2.8. I tested the 70-200 f4, f2.8 and the 70-300 IS, in the copies I got from a local store, the f4 was sharper than the f2.8 (both wide open) and the 70-300 was sharper than the f4. All tests were done at around 135mm on a 5D. Granted if I had stopped the f2.8 to 5.6 it might have been sharper, but I was testing which one had a better bokeh. So while not a true test, the 70-300 IS convinced me that it was as sharp as the others, about $700 cheaper than the f2.8 and 100mm longer,
.

The 70-200mm is a very nice lens but it's not much zoom (even 300mm falls short on occasions), so it depends what is important for you. I'd say goto a local store and try it out or better yet rent one and play with it. They are both great lenses.


For you it's a toss between range and speed, if you want both, get a 400mm prime :-)

1454
Canon EF Zoom Lenses / Re: Canon EF 70-300 f/4-5.6L IS
« on: September 19, 2011, 01:43:17 PM »
iowafirebird,

Amazing, gives me lots of hope :)

I love the way you blurred the cabbage white butterfly. Did you use CS4? How did you select the objects to blur? I love the PP you did to it.

1455
Macro / Re: Do Moths Have Fangs?
« on: September 18, 2011, 09:54:43 PM »
No fangs, but they have long tubular tongues coiled when not in use. Just like butterflies they drink nectar.

Dreamy!  What lens did you used fo rthe first pic?

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