Topics

1

Lenses / Lens sharpness and distance from subject

« on: April 26, 2013, 01:54:29 PM »

I was wondering whether and how much the distance from the subject affects sharpness of the image taken by different lenses (on same sensor). Is there any website or source where such information may be available for Canon lenses?

2

Third Party Manufacturers / Yeah, that is the future......

« on: April 01, 2013, 10:23:35 AM »

The newest revolutionary sensor technology is here...

http://www.lensrentals.com/blog/2013/04/wavelength-detecting-sensor-eliminates-bayer-filter-triples-resolution

and they will let you use your EF lenses too

3

Technical Support / AF Confirm. Chips and Camera Auto Focus System

« on: October 14, 2012, 08:11:49 PM »

I was thinking about this issue. What does the AF confirm chip do in conjunction with the camera AF system?

This is what I understand: When I am mounting an EF mount lens (from any manufacturer) on my canon camera, the processor of the lens lets the processor in the camera know, through the electrical contacts on the mount that a specific lens (focal length, max aperture, and lens ID) has been mounted on the camera. The programmable AF confirm chips also probably do the same thing (at least upto this point). Let's call it the lens id stage.

Now, when I am trying to Autofocus an EF lens, there is again an information exchange between the camera and the lens, which activates the lens AF motor to engage the focus elements of the lens (let's say we have chosen the center focus point only). When the split image on the focusing sensor at the base of the camera reaches a certain level of phase based difference/clarity (or whatever that is called technically) the AF point inside the viewfinder lights up and beeps. So my lens has acquired focus. The same thing happens while manually focusing the lens, except that the lens motor does not operate. Let's call it the focusing stage.

Now, then, what does the AF confirm chips do for non-EF lenses during this focusing stage? The chip has electrical contacts to complete the lens ID stage, but in the focusing stage it has nowhere to take the focusing information to take (as there is no focus motor in the lens). But still the focus points light up and beep when we gain focus. If the mount for the non-EF lens does not have any focus confirm chip then this beeping and lighting up does not happen. Does that mean, for the focus system inside the camera to work, we just need the camera to know that there is some "particular" lens mounted on the camera? So we just need to complete the lens ID stage. For non-chipped mounts the camera does not know that there is any lens at all on the camera and so the focus system keeps on "sleeping". Is that how the thing works? Any clarification is welcome.

4

Technical Support / Event Shooting: Camera Picture Style Setting

« on: October 09, 2012, 07:53:35 PM »

Hello All,

I have to shoot a group event next week. It will be organized completely indoors. And it is unpaid (In any case I am not a pro photographer). I am the sole member of the group who has some enthusiasm in photography (read who has two cameras and a couple of flashes), so the duty has fallen upon me. It is not a lifetime event for anyone (that is it is not a wedding, or engagement or anything as such).

I do not want to spend a lot of time on post processing (in fact it will be best if I do not have to spend any) in front of my computer. So I am planning to take the photos in Large/Fine JPEG format (will enable me to take a lot of "snaps" with my current cards). Unfortunately, I have never done this - that is never taken photos in JPEG format. Even before I bought my first (digital) camera, I was reading about photography and so the first photo taken by me with my first camera was a in RAW format.

I am looking for your help in deciding which picture style should I choose to shoot? Standard or Portrait or Landscape or Neutral or Faithful? If I go for User Defined styles then what should I choose as values of the four things that we can choose inside each of the photo styles. I shall use a 40D and a 50D (with a 12-24 Tokina, and an old EF 22-55mm Canon lens, may be a a few with 50mm 1.8 II).

Thank you for your time and help.

5

Third Party Manufacturers / Sigma 70-200 OS

« on: September 25, 2012, 08:33:40 PM »

Probably most of you here swear by Canon's 70-200L IS II, and for excellent reasons. From numerous forum posts here I can understand this is one of the best zooms produced, period. But I am not looking for any more info about Canon's offering. What I am looking for is personal experience of those of you who might be using the Sigma 70-200 OS. It would be great if any of you actually used both the Canon and the Sigma. Would you please care to share your opinions and experiences? I am not a professional photographer, so justifying buying the Canon is almost impossible for me. The similar offering from Tamron does not yet have OS/VC/IS. So it would be a great help to learn from your opinions and experiences about the Sigma lens. Thank you all in advance.

6

Lenses / Tamron 60mm macro

« on: September 25, 2012, 11:57:34 AM »

Anybody has used this lens? On paper it is 1 stop faster than canon's equivalent, and on APS-C has a nice 90-95mm equivalent field of view for portraits. Any experience?

7

Lenses / Old manual focus 50mm: Sharpness

« on: September 23, 2012, 06:59:29 AM »

I am planning to buy an old manual focus (with aperture control ring on the lens) 50mm lens for basically reverse lens, and extension tube+manual lens based macro work. I am specifically not looking to buy any of the current auto focus macro lenses (or the non auto focus Zeiss glasses). The first reason is of course price (for the time being) and the second reason is I pretty much like the whole ritual of macro photography using the above two methods.

Those of you who have used the different manual focus 50mm lenses produced by different manufacturers (Canon FD, Nikon, Pentax, Minolta, and others) during the film era (or may be even today) could you please share your comments about the sharpness of the lenses that you have used. I am trying to figure out which one out there might be the sharpest (if there is any specifically).

If you think a different lens of a different focal length would be better for my intended purpose then also please share your thoughts.

Any help is most heartily welcome.

8

Lighting / Wireless Flash Trigger+Wireless Shutter Release

« on: March 25, 2012, 03:12:09 PM »

Dear CRians, I have a question regarding wireless flash trigger and wireless shutter release. I have not yet ventured into the usage of a "proper" flash (used only the on camera one till now). However, I am planning to buy one speedlite in near future. Along with the flash I want to buy one wireless (radio!) flash trigger (which I think comes in two pieces. One piece attaches to the shoe of the flash and the other to the hotshoe on top of the camera). The other thing that I want to buy is a wireless (radio!) shutter release. Now those of you who have used such a set up, could you please tell me which brad do you use and share your experience. Thank you for your time.


__________________________________________________
_{EOS 40D, EF 50mm f/1.8 II, 85mm f/1.8, EF 22-55mm, some extension tubes}

9

Lenses / Are EF-S lenses compatible with FF bodies

« on: March 14, 2012, 01:14:57 AM »

I thought EF-S lenses are not compatible with FF bodies. But then I saw this bundle being sold by adorama

http://www.adorama.com/ICA5DM2L51.html

What is the reasoning here? EF-S 15-85 is compatible with 5DII or just a marketing ploy or mistake or what?

10

Lighting / My new tripod

« on: March 08, 2012, 09:59:01 AM »

I just received my first tripod, and ball head. Thought that the following information and photos might help some of you who might be thinking about buying a tripod. Although this is not strictly about lighting but I do not know under which other topic I could post this, so here it goes.

Disclaimer: I am not advertising either the tripod or the ball head, just putting up some information about my new gear.

The model: Giottos MT 9370 (Tripod).
First impression: Pretty heavy as it is an aluminum tripod (the CF ones are quite expensive for my budget). It has four part legs with twist locks. The locks work pretty well in locking the legs but are slightly rough on the hand. If I extend the legs to their full length, then even with the central column kept at the lowest (normal) position, the tripod extends well above my height (I am approximately 5'11''). The leg diameter/radius looks robust and dependable. The multiposition neck (I am not sure what else should I call it) can hold the central column in almost any conceivable position. The central column can be locked in the revers position as well (with the multiposition neck both in its normal position and open position which creates an off-center central column possibility). As usual each of the legs can be locked in three different positions (low, medium and high).

The ball head: Smith Victor BH5
Seems sturdy and nice. In future I want to get an EF 100-400mm lens and I think this ball head shall be able to support that. right now though, with my canon 40D and 50mm 1.8II, 85mm 1.8 and 22-55mm lens this head seems a bit larger than necessary.
Within the budget that I had this was the best that I could afford and I am satisfied.

I am posting some photos below. If you have any question about these particular models then I shall be happy to answer them to the best of my abilities.