Say Cheese! Pt 3 (Photography Reflection)

Hello all.

Thanks for the depth of field information Sophie; I was a bit confused myself. Reading the Wikipedia article made my head swim! But am I right in thinking the following?

• The larger the depth of field, the more of the image in front of and behind the focus point is also in focus. Therefore, for intra oral shots the larger the depth of field the better.
• The depth of field can be increased by increasing the lens f-number (a setting on the lens). Therefore for intra oral shots we should set the lens f-number to the largest value available on the lens.
• The ‘aperture’ is the diameter of the opening that allows light into the lens. The aperture is decreased by increasing the f-number. Therefore the smaller the aperture the better the depth of field.
• A macro lens is used for intra oral photography because it is ideal for close up shots. However, macro lenses have a long focal length. A lens with a shorter focal length will give a greater depth of field.
• The closer the camera is to the subject, the smaller the depth of field. Therefore, to increase the depth of field the camera should be positioned further away from the subject.

Are these correct?

I also wanted to clarify what is meant by the term ‘focus point’ on the self assessment table. Is the focus point what the camera is aimed at (i.e. the object in the middle of the photo), or is it the centre of the depth of field (i.e. the least blurry depth of the photo)?

Thanks. I hope this all makes sense!
Nick

Taking burst shots

I have taken the advice of other students and taken a burst of photo's instead of just taking one. When I printed out the photo's I noticed something... all the photo's I took in succession were exactly the SAME! Maybe slight differences, but I didn't have 3-4 different photos of the same area. 

Here is my advice, instead of taking multiple photos one after another (which will all probably turn out the same because you don't really adjust much), just relax and take a good photo. Take multiple photos, but make sure you adjust the focus or positioning because if you don't and the first photo is shit, the other 3 probably will be too...

Just my thoughts

Acacsia  

Depth of Field

I have received a few comments on DOF re: what is it?  and how should you comment on it in your critique. In your Dental Imaging Guide, there are questions which guide you through an understanding of the Depth of Field accompanied by references that will help you find your answers. 

I have attached a few links to resources that may help you.

http://en.wikipedia.org/wiki/Depth_of_field

From the following article:

http://www.dentistry.co.uk/articles/articles_detail.php?id=396

"The macro lens you use should have a small aperture to maximise the depth of field. An aperture or f-stop of 32 is ideal for dental photography because many shots require a significant depth of field.

Depth of field: This is the ability of the areas in front of and behind the main subject to field remain in focus. Three things effect the depth of field: focal length of the lens, aperture and distance from the subject. A larger aperture (f-stop number) will render a shallower depth of field. A longer focal-length lens will also give a narrower depth of field. Finally, the closer the camera is to a subject the narrower the depth of field will be."

If you are panicking that you have not taken any valuable images and you dont want to inconvenience your patients any more, just take a moment to reflect on the aperture settings etc.. and take a few more on one of your colleagues so that you dont end up thinking you are "bad" at taking dental photos. It is important to build your confidence up. Grab a colleague who is confident at taking photos and have one more go at it.

Sophie  

 

Say Cheese! Pt 2 (Photography Reflection)

Hello all.

Apologies for my recent lack of posts, I FINALLY managed to get my blogspot account working again (something about needing to reset my Google Account??)

Anyway, since my last post, Luke, Jen Cao, Jasmina and I have had a few more sessions taking dental photographs on each other. Our photo-taking procedures have definitely improved in accuracy and efficiency since our first photography sessions in first semester. Working as a group we have become far more confident in our positioning of ourselves, the camera, the patient and any mirrors used. Furthermore, our knowledge of what camera settings and flash devices to use for each particular photo type has become second nature.

At one point a large percentage of the photos I was taking were coming out wrong (see below)

instead of













At first I thought it was an error with the exposure time (hence the burring) or that I was pressing the button wrong. Then we realised the flash was not functioning properly and we tracked down some more AA batteries for it. It worked fine after that. So if you guys get the same problem you know what to do!

The following are some techniques and lessons I have learnt to make taking photographs easier:

• Take the photos as a series of ‘bursts’. Take a small number of photos in quick succession. That way, if the patient blinks or moves momentarily, you should still have other usable photos without having to set up the shot all over again.
• Don’t forget to check the camera’s screen every now and then. Your last photo should pop up on the screen just after you take it. Take a quick look every now and then because the actual photo can sometimes look quite different to what you see in the viewfinder. This saves you from taking a stream of photos with a common flaw (such as a flash or exposure time error).
• Also, once you are finished taking photos of that type, use this time to check through them all on the camera to be sure you have at least one that is usable. That way if you need to take any more, you don’t have to set everything up again.
• When taking extra-oral shots, the amount of shadow can be altered by the relationship in distance and angulation between the flash, patient and the wall behind.

I used to find on occasion that the horizontal framing of the subject in the camera's viewfinder was different to that in the resulting photograph. I predict that this may have been due to the horizontal angulation of the camera at the time. This could have meant that I was looking through the viewfinder on a slight angle, and therefore seeing a different composition to the lens. If you have this problem, try looking through the viewfinder from a more square-on angle. You could also try taking a sweep of the shot, where you line up the camera and take a series of photos moving slightly horizontally (e.g. left to right) each time.

Finally, I can not overemphasise the importance of the recommended texts provided for us to read through. These texts give information on every aspect of dental photo taking, and most importantly, provide examples of ideal dental photographs to assess yourself against and strive to match.

Thanks. Hope this helps.

Nick

to crop or not to crop....

hey guys
the criteria for the cinical photography assignment states we are not to submit edited pics - does this include flipping the lateral views taken in the mirror??
are we allowed to crop the pics to remove the outer edges??
i agree with u Acacsia - i had Dr Lew the dentist on board on fri help me take pics on my pt, very time consuming (A LOT longer than 10 mins!) and the pt found them quite uncomfortable as only 4 weeks ago her jaw was dislocated from having 4 x exos of her 8's... how's my timing!!
if anyone knows about the cropping let me know
xx Amy

Patient photo's

Hi all,

I finally took my photo's on a patient, and it was hard. My tutors told us (and Nick will be able to back me up on this) we had 10 minutes to take the entire series. Thats probably fine if you have a lot of experience, but I took the other photos on class mates back in the first term holidays! So I was rusty. I felt really pressured to take all the photos so I just rushed through them, I didn't even review them to see if the were OK. My strategy was to just take 2 or 3 one after the other with slight adjustments and hope for the best! I still haven't seen the the photos...

Did anyone else feel like this? I know its uncomfortable and the patient doesn't want to be sitting there for a whole hour, thats not fair. I just would have like a little more time...

Maybe I should have practice some more on students before I went to the patient.

Acacsia