Aperture and close ups

[CLINTOS]

Hi, I'm new to photography.

I was wondering about aperture and close up's, along with sharp images.

I read that with a wide aperture that you start to lose image quality, is this true?

And does leaving the shutter open longer at a aperture of 1.8 correct this problem? providing you are using a tripod and remote shutter?

what about mirror lock up?

I'm trying to use extension tubes and a 50 mm lens while getting the sharpest image possible, while keeping the entire coral in focus. at what aperture will I start to lose the edges of this pic:

I think it was taken with a long shutter speed and a low mm extension tube, 50 mm lens with the aperture wide open at 1.8.


I'm looking to take recordia yuma photo's similar to the maxi mini anemone in the future

Just wanted to know where I should set the aperture to get the entire image in focus while getting the best image quality, and not losing the edges of the image to being out of focus.

or should I consider using a narrower aperture and just crop the pic?

 

[pyroboy1der]

Reading this post it seems to me that you still don't quite have a good grasp on the fundimetals yet. Here's a breef primer

Aperature (f-stop): Controlls the size of the hole that light gets into your camera through. Small numbers (f/1.8) Are big holes and large numbers (f/32) are small holes. When using a large aperature (F1.8) there will be a very limited field that is in focus. This is a plane that is PARALEL to the sensor(eg. the fish you want to take a picture off is in focus but the rock just a few inches behind it is blurry). Using a smaller aperature will make that plane larger (front to back as you look at it as the shooter) until you get to some very small aperatures where almost everything is in focus (eg. your whole tank is in focus as well as the room behind it)

Shutter speed: controlls how long light is allowed onto the sensor. It is measured in fractions of a second so when your camera says "1000" it meens 1/1000th of a second.


What this meens to you:
The more of a picture you want in focus the smaller aperature (larger number) you want to use. But... because a smaller hole doesn't allow as much light in as a big one you will also need to slow down your shutter speed.

So if you were shooting at f1.8 and 1/100th but you are getting things that are blurry that shouldn't be you could try f2 at 1/50th or f2.4 at 1/25th

 

[ggrillo]

If you stop the aperture down to f/4 or even f/2.8 the pictures will be sharper and you just compensate by using a longer shutter speed. Make sure you turn your pumps off so you don't get any motion blur. Also you can always bump up your ISO to 400 or 800 (sometimes more) depending on what camera you are using.

 

[CLINTOS]

Thanks, I'm kind of getting it.


Should I do everything I can to avoid going above 100 iso? if I can get the shot otherwise, doesn't it get more Grainier the higher the iso? or that anything below a specific iso not degrade the image?

shutter speed:

say I was able to take a shot at 1 second shutter speed and the pump's are off, would this give me a better image then 1/60th second? I know it will let in more light but will it let in more image quality?

Sorry for the question's, I just want to get this out of the way and not think about it.

 

[hobbzz]

What camera and lens are you using?

 

[CLINTOS]

canon eos rebel t3 and a 50mm 1.8 lens, along with kenko extension tubes,12,20,36mm.

I read that a 50 mm lens and 50mm of extension tube get's you 2 x life size providing that you can get close enough to the subject, is this true?

 

[Reef Bass]

It sounds as though you are confusing depth of field with diffraction.

Depth of field (amount of subject in focus in front and behind the focal plane) varies with aperture. The wider the lens opening, the less depth of field.

Diffraction occurs at smaller lens opening / higher f stop number.

Because you are using extension tubes instead of a macro lens, your depth of field is going to be razor thin.

I would also suggest shooting in raw and adjusting your white balance during post processing to get more accurate colors.

 

[pyroboy1der]

Thanks, I'm kind of getting it.


Should I do everything I can to avoid going above 100 iso? if I can get the shot otherwise, doesn't it get more Grainier the higher the iso? or that anything below a specific iso not degrade the image?

shutter speed:

say I was able to take a shot at 1 second shutter speed and the pump's are off, would this give me a better image then 1/60th second? I know it will let in more light but will it let in more image quality?

Sorry for the question's, I just want to get this out of the way and not think about it.

1) gong to a Higher ISO will add "grain" to your photos but you usually can't notice it for the first few steps.

2) You can't "let in" more image quality, just light, when you take a well exposed picture you always let in the exact same ammount of light. Imagine moving water through a straw for 60 secons vs a 2 inch pipe for 2 seconds. You still move one gallon of water. Taking photos is the same way. Higher ISO=Faster shutter and smaller aperature. Faster shutter = higher iso and larger aprature. Large aperature= low iso and fast shutter speed
The only way to make sure you piture is "high quality" is to use god equipment and not push the ISO too far.

3) If you want to just take pitures and not think about it a DSLR is probably not for you. For EVERY photo i take i think about all these things and plenty more . its the diference between taking pictures and taking photographs.

 

[CLINTOS]

From what I understand, is that above f22 you get distortion and that F8-11 is the sweet spot on average, for a sharp image.

 

[Dre59]

This is great info.. Can someone post some pictures just to give some examples for us newbies

 

[Misled]

Here's a quick example I did for a class. The camera was on a tripod, 10 feet from the ladder. The ladder was 10 feet from the dumpster. Camera in AP and the only change made was stepping the aperture one stop down, (higher number), for each picture. A cheep sigma lens was used and a remote shutter was used also. The focus point was the label on the ladder.

Highest aperture. f3.3

f4

f4.8

f5.6

f6.7

f8

 

[Misled]

f9.5

f11

f13

f16

f19

f22

 

[Dre59]

Misled, you are a BIG help here on RC :thumbup::thumbup:

Just want to say Thank you! Between reading and practice. My photo skills have improved much better and getting the concept with a DSLR. Just wish everybody will post their settings when pictures are shot

 

[Misled]

Thanks Dre. You can download an EXIF viewer. On most, this will give you all the info you want. With mine, because I limit file size with Photoshop elements, the data is removed, but if anyone asks, it's not a problem. Personally, the data someone else uses doesn't help me much. 90% of the time, I shoot on the fly. When you get through the basics of how the three big things work, (ISO, Aperture and Exposure), everything just automatically computes in your mind. Shooting in manual and checking the results as you go through your images really helps give you an understanding of what will happen when you press the shutter release.

 

[Hookup]

From what I understand, is that above f22 you get distortion and that F8-11 is the sweet spot on average, for a sharp image.

Based upon this comment and your OP... I think you might have read (correctly) that lens's have problems with keeping images tack-sharp when used at their extremes. Most (All) lens's have a sweet-spot within their operating range that provides optimum results. As pointed out above, this is typically between F8 and F11.

That said, this thread is chocked-full-of great overviews and other bits of information that definitely give you a 101 on shooting with your DLSR.

BTW, great little lens that F1.8 50mm prime. I love mine very much... Looks kinda goofy when i have the battery-pack mounted and a flash on the body with this teeny-tiny lens... but the results are outstanding for most lens's, then add to that the cost... it blows my mind every time i use it.


Great first photo btw. I suggest looking up the image stacking technique and playing around with it to see if you can get the result you are looking for. Often times this has been done for some of the most amazing macro shots.

 

[ggrillo]

A good rule of thumb that I usually shoot by is, "f/8 and you'll be great"

 

[BlueCorn]

A good rule of thumb that I usually shoot by is, "f/8 and you'll be great"

Normally, I like to let the requirements of the shot dictate my aperture. Learning to manage a scene front to back, as well as side to side, is often the difference between a good shot and a bad shot.

If there are no other pressures dictating aperture, f/8 is indeed a good choice. If gives reasonable DOF and most lenses are sharpest somewhere in the middle of their aperture range.