Continuation of AF Assist v2 post.
The change o the op-amp did not do the trick as expected. In fact even though the NE5532 has a much quicker slew time, I didn’t make a difference. In fact I think it made things worse. Continue reading
Preparations for the music festival: a list of what I should pack, and take with me.
Photo gear equipment:
– Camera (+backup)
– charge all batteries (AA and camera batteries)
– clean all lenses
– tripod :make sure all parts are there.
–
Clothing:
– rain coat
– hiking boots
– assortment of clothing
–
Computer:
– get 250gig drive cleaned out, got a new 500gig and formated.
– take cable to tether phone to laptop (USB to microUSB)
– install Bibble on computer
–
Others:
– earplugs
– advil
– pepto-bismol pills
– Cliff bars
– energy drink (buy in MTL)
– Allergy medication
– nail clippers
– bathroom supplies (soap, shampoo, q-tips, toothbrush, tooth paste)
–
Daypack:
– laptop + charger+cables + USB drive (to format)
– water bottle
– snacks (fruit, crackers)
–
Things to keep in mind while shooting:
– remember the 1/focal length rule. So for the 85mm lens, shoot at 1/125, the 135mm lens shoot at 1/150 -1/200. Up the ISO to get the shutter speed required. Better to have a sharp noisier image, then a blurred cleaner image.
– camera AF on AI Servo, Spot metering, use only the center AF point.
Continuation from this post. Build and experimentation log continues.
I built the unit and tested it last week. The laser seemed lower power then the first one I built (which was just the laser pointer hooked up to a set of 3 AAA batteries along with a pushbutton).
Last night I had time to take a multimeter to it. The laser LED is seeing a total of 3.4V from the output of the LM358 OpAmp. The rail voltage was 4.6V (3 AAA bateries) yet the maximum I could coax the output to put out was 3.3V – 3.4V. This explains why the laser beam seemed weaker at first try.
I’m really going blind here using an OpAmp. Did lots of googling, but found nothing to explain this behavior. I tried several LM358, and they all worked the same way. It must be how they work.
So after an hour of dead end attempts and research, I decided to add a 4th AAA battery (for a total of 4 AAA) to give the op-amp 6V, and that did the trick. Now the laser LED sees 4.3-4.4V, and the brightness is back to what I remembered. Continue reading
I built a controller for the laser pointer (so it would be controlled by the camera’s hot show) as per the directions given on this post on fred miranda forums. The OpAmp I used was two LM741. However as I found out after I built the setup, the LM741 needs over 10V to power it, which is why I was having no success with that build.
My power source is 3AAA batteries (4.5V).
After some searching , I bought some LM358 op-amps, which will run on any voltaqge between 3-30V which should run just fine on 4.5V. Also, there are two op-amps in each 8pin chip, so I can make the board smaller.
I also bought a few NE5523 op-amps (which have the same pinout as the LM358) just so I have another option.
Below is a schematic of what I will be building later today:
I am happy with the way the Discogs Album Release plugin is coming together.
Version 1.0 does what I need it for now.
Version 2.x has new features I want to add. The main feature is adding an audio preview of each album so that you can listen to the tracks directly from my site. This will only work if Amazon has the album on their database, thought the majority of albums I’ve come across are on Amazon.com.
Using code from this site and this site, I’ve made a php script that searches the Amazon.com database for a keyword (artist + album) and returns the ASIN # (This is the unique number given to each amazon item).
If I don’t get a number back, then the album doesn’t exist. If I get a number back then I can add a music player that pops up so the viewer can listen to the Amazon previews of the tracks and maybe buy them.
This check needs to happen every time the page is loaded, so that if in the future when the album is added to amazon.com it will show up. On the other hand, is the complexity of doing this worth the work, considering I doubt many people will be looking at month old releases…
Another thing for 2.x is to build some sort of widget that shows a list of the latest albums. Maybe have it update every time the page is loaded and display the latest releases. This brings up the question of the necessity of the daily digest version of the album releases…
I also signed up for a merchant account so if a user buys the album, I get a cut of the actions. Wohoo!
lcd is the command.
The new version of the AF Assist tool will use a similar laser pointer but have the function of it be controlled by the camera and not the push button.
I know there is a pin on the hotshoe that gets energized by the 1/2 push of the camera shutter button. This is the AE-Lock feature of the camera. I know this because my wireless trigger has an LED on it which goes green at the half press of the shutter button. The LED goes red with a full shutter button press.
What I want to do is trigger the AF assist light to come on when the AE-Lock (1/2 press of shutter) button is pushed, and turn off the AF Assist light when not pushed.
The other thing I need is for the AF light to momentary go off when the flash is triggered so not to record the AF light into the image.
UPDATE : See this post for the first builds
Last september (2010) I wrote a blog entry about hooking up a laser pointer as an Auto Focus assist light for a camera. The need came up because I wanted AF assist in AI Servo focusing mode of my DSLR. Currently to my knowledge all Nikon and Canon DSLRs will only put out the flash AF assist beam until focus is achieved. After that if the (if the camera is in AI-Servo focus mode) if the subject moves and the focus changes, you’re out of luck in dark situations because the AF assist beam will not continually come on to keep assisting the focus.
The previous look at using a laser pointer as an AF assist tool, I had very little success with that projects. Last week I came across the laser pointer again and new thoughts/ideas came to mind.
So I rigged a laser pointer to a bunch of batteries and a push button to act as an Auto Focus assist to my Canon 40D. The results are spectacular.
I’ve already started working/thinking about the next version of this. Updates on the AS Assist Tool V2.x will be here.
This is what I did, and how it worked.