Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-10-2011, 04:46 AM   #16
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,957
QuoteOriginally posted by paws4critters Quote
Sorry, to be a bother to all y'all. I am fairly new to cameras that you have to focus. I have always liked them, but never understood them. Now, I am trying to understand them. I can take photos with them, but I really could not explain what I did except focus and shoot.

I really would like to understand the Macro because I see really great photos I would love to shoot myself.

These are the two lenses I have and what they say on them...

Tamron: Aspherical LD XR DiII Tamron AF 18-200mm 1:3.5-6.3 [IF] MACRO 62 A14
Before the 62 is a symbol that resembles a computer zero, you know a zero with a line through it.
At the back of the lens, where it attaches to the camera, the numbers left to right read 200, 135, 100, 70, 50, 35, 18
At the front of the lens, farthest from the camera, two rows of numbers for feet & meters read (ft) 100, 20, 8, 5, 3, 1.48; (m) infinity symbol then 30, 7, 3, 2, 1, 0.45
Pentax: Pentax 18-55 II SMC Pentax DA CE (and a number like a serial number)
At the back of the lens, where it attaches to the camera, the numbers left to right read 55, 45, 35, 24, 18
At the front of the lens, farthest from the camera, two rows of numbers for feet & meters read (ft)7, 3, 2, 1.5, 1.15, .82; (m) 2, 1, 0.6, 0.45, 0.35, 0.25

While playing with the two lenses, I found the Pentax appears to get a little closer to the subject than the Tamron when using Macro. I am sure all y'all are probably rolling your eyes by now, but, here comes the stupid question, does the Macro have something to do with the ft/m numbers... and are those numbers telling me how far I have to be from the subject for it to focus?

I am trying to take good photos worthy of selling. I realize there are tons of folks out there doing the same. Could anyone tell me how they would rate these two lenses?

Appreciate it. Sorry to bug everyone with such novice questions.
Thanks!
All lenses have a minimum focus distance. With the Tamron, your minimum focus distance is about .3 meters, with the kit lens, it is 9.8 inches. Neither one is a true macro lens -- they just have some close focusing ability.

True macro lenses allow for a minimum of 1:2 magnification on the sensor. This has nothing to do with f stop numbers or, even focal length. The numbers you are reading have to do with focus guiding and help with manual focusing.

Don't hesitate to post more questions in the beginner's area...

04-10-2011, 07:04 AM   #17
1,000,000th Poster!




Join Date: Apr 2010
Location: Montreal, QC
Photos: Gallery | Albums
Posts: 172
QuoteOriginally posted by paws4critters Quote
Sorry, to be a bother to all y'all. I am fairly new to cameras that you have to focus. I have always liked them, but never understood them. Now, I am trying to understand them. I can take photos with them, but I really could not explain what I did except focus and shoot.

I really would like to understand the Macro because I see really great photos I would love to shoot myself.

These are the two lenses I have and what they say on them...

Tamron: Aspherical LD XR DiII Tamron AF 18-200mm 1:3.5-6.3 [IF] MACRO 62 A14
Before the 62 is a symbol that resembles a computer zero, you know a zero with a line through it.
At the back of the lens, where it attaches to the camera, the numbers left to right read 200, 135, 100, 70, 50, 35, 18
At the front of the lens, farthest from the camera, two rows of numbers for feet & meters read (ft) 100, 20, 8, 5, 3, 1.48; (m) infinity symbol then 30, 7, 3, 2, 1, 0.45
Pentax: Pentax 18-55 II SMC Pentax DA CE (and a number like a serial number)
At the back of the lens, where it attaches to the camera, the numbers left to right read 55, 45, 35, 24, 18
At the front of the lens, farthest from the camera, two rows of numbers for feet & meters read (ft)7, 3, 2, 1.5, 1.15, .82; (m) 2, 1, 0.6, 0.45, 0.35, 0.25

While playing with the two lenses, I found the Pentax appears to get a little closer to the subject than the Tamron when using Macro. I am sure all y'all are probably rolling your eyes by now, but, here comes the stupid question, does the Macro have something to do with the ft/m numbers... and are those numbers telling me how far I have to be from the subject for it to focus?

I am trying to take good photos worthy of selling. I realize there are tons of folks out there doing the same. Could anyone tell me how they would rate these two lenses?

Appreciate it. Sorry to bug everyone with such novice questions.
Thanks!
It's like having a cook who needs to make meals out of ingredients he doesn't know. He might get lucky, but most of the time it might not be too tasty. He needs a recipe book to start with.

I think you should start at the beginners section, and also find yourself a few good photography books like "understanding exposure". You need to understand what tools you have at your disposal and what they can and cannot do.

It's very important if you wish to sell your photos.
04-10-2011, 11:28 AM   #18
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
BTW, this whole thread really belongs in the Lens forum. Or the beginner's forum. There are probably dozens of similar threads on the basics of lenses in both forums that would be searching for before starting another.
04-10-2011, 12:34 PM   #19
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,957
QuoteOriginally posted by Marc Sabatella Quote
BTW, this whole thread really belongs in the Lens forum. Or the beginner's forum. There are probably dozens of similar threads on the basics of lenses in both forums that would be searching for before starting another.
Aren't you a moderator still?

04-10-2011, 02:12 PM   #20
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Yes, but I tend not to want to move a thread that has already been around a few days and has a bunch of responses. I'm just suggesting that, since it seems the thread is kind of drifting, that further discussion drift to a more appropriate forum. In particular, if someone feels like asking more questions relating to macro lenses specifically, that they do so in the Lens forum, and if they feel like asking more questions relating to the numbers printed on lenses in general, that they do so in the Beginner's forum.
04-11-2011, 11:46 AM   #21
Forum Member




Join Date: Dec 2010
Location: Silkeborg, Denmark
Posts: 82
Original Poster
QuoteOriginally posted by Marc Sabatella Quote
A 100mm macro lens *is* a telephoto lens. So I'm not sure what distinction you are trying to make here.
I guess what it comes down to, is this... Can AF be fast enough on a macro, to be used for action shots, so they look sharper, instead of using a more traditional lens like a 200 mm lens? I know on my 105 mm macro, the AF is no where near fast enough to be used for action, so I wonder if this is a general thing for macros.

Also, sorry for putting this in the wrong forum, I'm also new here
You can move it, if you please.
04-11-2011, 11:48 AM   #22
Forum Member




Join Date: Dec 2010
Location: Silkeborg, Denmark
Posts: 82
Original Poster
QuoteOriginally posted by imtheguy Quote
Yep. 1:1 is easy to find in $100 (used) 100mm lenses if that is the main requirement.
That is interesting. Am I correct in assuming that a 1:1 telephoto lens will produce a more detailed image over a 1:2 with otherwise equal specs?
04-11-2011, 02:43 PM   #23
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
The question about AF speed and how it relates to image sharpness when dealing with moving subjects is interesting. The shutter is still open the same length of time - and only *after* AF has been achieved - so no, a macro lens shouldn't be any worse in that respect. But of course, you may well have missed the moment you were trying to capture because of the slower AF. Or, if you were specifically timing your shot to coincide with a moment of relative inactivity, that will be harder if the AF speed is slower. Some macro lenses have focus limiters that would prevent that from being an issue, but not either version of the D-FA 100 as far as I know.

As for the 1:1 macro being "more detailed" than 1:2, well, the maximum subject will be *bigger*; that much is certain. If both are shot from same distance, then the subjects will be the same size, and there is no reason to assume the image from the lens that happens to be *capable* of 1:1 would be any more detailed. Either one might be sharper, or they might be about the same But sure, if you moved in closer with the 1:1 than with the 1:2, you'd get more detail than you did when shooting from the same distance as with the 1:2.

And as you may have noticed, I have gone ahead and moved this to the lens forum. Welcome, BTW!

04-12-2011, 03:54 AM   #24
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,957
QuoteOriginally posted by mikknu Quote
That is interesting. Am I correct in assuming that a 1:1 telephoto lens will produce a more detailed image over a 1:2 with otherwise equal specs?
As Marc says, not necessarily. 1:1 Macro photography is really, really hard. It requires good stabilization and lighting. Obviously the lens does play a part, but good technique is probably more important in the whole scheme of things.
04-12-2011, 07:30 AM - 1 Like   #25
Inactive Account




Join Date: Dec 2008
Location: Ames, Iowa, USA
Photos: Albums
Posts: 2,965
QuoteOriginally posted by mikknu Quote
That is interesting. Am I correct in assuming that a 1:1 telephoto lens will produce a more detailed image over a 1:2 with otherwise equal specs?
For a given lens focal length, f-stop, etc the only thing that affects image magnification is how far it is from the sensor. That means there need be no inherent optical difference between a lens marked 1:2 and one marked 1:1.

At least for older (non-internal focus) lenses, the only difference between a 1:1 and a 1:2 macro lens is how far the focusing mechanism moves the lens from the sensor. You can take a 1:2 lens & put it on an extension tube equal to half its focal length; you now have a 1:1 lens!

If your camera's sensor were perfect you could take a photo at 1:2 and enlarge it by a factor of 2x and have the same detail; unfortunately your sensor is far from perfect and the enlargement will not have some detail that would have been in the 1:1 unenlarged image from the same lens.

So the answer to your question is yes, a 1:1 lens may show more detail than a 1:2 lens but it doesn't necessarily mean the lens is any better.

Last edited by newarts; 04-13-2011 at 11:13 AM.
04-13-2011, 09:04 AM   #26
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
Any lens will focus closer by adding extension. For very close and macro work, aperture automation is useful, but autofocus likely isn't. The cheap and easy way to add extension to an auto lens is to get a couple old TC's (teleconverters) with A-type contact pins, and remove the glass. These are typically about 25mm deep, so two of them are 50mm. These allow macro work with a DA18-55 kit lens.

How satisfactory such a rig would be, is another matter. Macro and enlarger lenses are designed for edge-to-edge flatfield sharpness, and non-macro lenses usually have more field curvature. The kit-lens+extension rig would be good for dreamy flower shots, and not so good for shooting stamps, circuitry, other stuff where flatness matters. So, subject matter can determine lens choice.

QuoteOriginally posted by paws4critters Quote
I am fairly new to cameras that you have to focus. I have always liked them, but never understood them. Now, I am trying to understand them....
Understanding lens inscriptions is good.

QuoteQuote:
Tamron: Aspherical LD XR DiII Tamron AF 18-200mm 1:3.5-6.3 [IF] MACRO 62 A14
Before the 62 is a symbol that resembles a computer zero, you know a zero with a line through it.
At the back of the lens, where it attaches to the camera, the numbers left to right read 200, 135, 100, 70, 50, 35, 18
At the front of the lens, farthest from the camera, two rows of numbers for feet & meters read (ft) 100, 20, 8, 5, 3, 1.48; (m) infinity symbol then 30, 7, 3, 2, 1, 0.45
That lined-zero before the 62 is theta and shows the front thread size: 62mm. This tells you what filters, adapters, hoods etc will fit.
The 200-135-70-35-18 sequence are zoom focal lengths, waypoints in the 18-200mm focal range.
The numbers for feet and meters are distances; the MFD (minimum focus distance) is 1.48 feet / 0.45 meters.

QuoteQuote:
Pentax: Pentax 18-55 II SMC Pentax DA CE (and a number like a serial number)
At the back of the lens, where it attaches to the camera, the numbers left to right read 55, 45, 35, 24, 18
At the front of the lens, farthest from the camera, two rows of numbers for feet & meters read (ft)7, 3, 2, 1.5, 1.15, .82; (m) 2, 1, 0.6, 0.45, 0.35, 0.25
The II, SMC, DA, CE are part of the lens model name. We'll usually call it the DA18-55 II.
Again, the 55-45-35-24-18 sequence are common focal lengths, so users can pre-visualize the FOV (field of view).
And the distance scale shows that the MFD is 0.25 meters / 0.82 feet / 9.84 inches / pretty damn close.

Adding extension changes those focus distances, but not the focal lengths. So, set a lens to 24mm, add a 25mm tube/TC section, and your magnification is [ EXTENSION / FOCAL.LENGTH ] = 25/24 = ~1:1 or 1x. Add 50mm extension and magnification is 50/24 = ~2:1. Or add 50mm extension to the lens set at 55mm and magnification is 50/55 = ~1:1, but with a greater working distance. (That's an oversimplified formula that works in this instance.)

Adding extension also affects effective aperture. Here, you can still control the aperture from the camera, so you could maybe set the lens to f/4. But light is reduced by an aperture factor of MAGNIFICATION+1. So with 1x magnification, light is reduced by 2 f-stops, to f/8; with 2x magnification, it's reduced by 3 f-stops, to f/11. Magnification eats light. That's why tripods and/or external lights are often necessary for macro work.

Longer focal lengths let (or forfce) you to work further from a subject. Longer focal lengths also require much more extension, in order to gain magnification. No single unreversed lens can focus closer than its focal length, which is also where magnification will be greatest. Going 1:1 at 18-24-35-55mm is probably suitable for studio work in controlled conditions; 80-100-135-150mm are much better for field work, so you don't scare awsay bug by sticking a big lens too close.

Those are some macro/closeup basics. You might look for books on macro shooting. Some say that macro shooters are the happiest photographers. So, GET HAPPY!
04-13-2011, 10:37 AM   #27
Forum Member




Join Date: Dec 2010
Location: Silkeborg, Denmark
Posts: 82
Original Poster
QuoteOriginally posted by Marc Sabatella Quote
As for the 1:1 macro being "more detailed" than 1:2, well, the maximum subject will be *bigger*; that much is certain. If both are shot from same distance, then the subjects will be the same size, and there is no reason to assume the image from the lens that happens to be *capable* of 1:1 would be any more detailed. Either one might be sharper, or they might be about the same But sure, if you moved in closer with the 1:1 than with the 1:2, you'd get more detail than you did when shooting from the same distance as with the 1:2.

And as you may have noticed, I have gone ahead and moved this to the lens forum. Welcome, BTW!
QuoteOriginally posted by newarts Quote

So the answer to your question is yes, a 1:1 lens may show more detail than a 1:2 lens but it doesn't necessarily mean the lens is any better.
Well, I guess what I have here is a very good reason to bring both lenses along next time and simply try to take shots with either lens to make some comparisons.

Thanks again for your replies, will need to read and test some more to fully grasp this.

Also, thanks to everyone else who replied to this thread
04-13-2011, 10:52 AM   #28
Veteran Member
sterretje's Avatar

Join Date: Dec 2008
Location: Roodepoort, South Africa
Photos: Gallery | Albums
Posts: 3,534
The closer you can get, the bigger the subject will be on the sensor (photo). This applies to every lens.

Your Tamron can get to 45 cm, your Pentax to 25cm. With your Pentax set to 55mm (focal length) and the Tamron set to 55mm and both as close to the subject as possible (25cm and 45cm respectively), the image produced by the Pentax will be larger and therefor closer to the definition of macro (1:1 magnification or better).

I think the Pentax achieves 1:3 magnification under those circumstances; don't know about the Tamron.

62 on the Tamron is the filter diameter
200, 135, 100 ... 18 on the Tamron and 55, 45 ... 18 on the Pentax is the focal length that you have set the lens to
And the meters/feet scale is the distance to the subject that is in focus.
04-13-2011, 12:29 PM   #29
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by imtheguy Quote
I believe it, but then I can't explain why every quality prime can not be as sharp as a lower priced Macro lens. .
Macro lenses are, as was already mentioned above, the sharpest lenses (in general). This is due to several factors, one of it being, that they usually have a very flat focal plane. This contrasts the typically more convex focal plane of standard lens designs.

The flat field of a macro is needed, because of the short working distances, which go hand in hand with an accordingly narrow depth of field. A standard lens design will often only get the center sharp at such short distances (and add some spherical aberration at very short distances, which sets a limit to the near focus).

On top, macro lenses are usually (with some very recent exceptions) slower, than normal lens designs. Fort many years a 50/4 or 100/4 macro was the norm, whereas you could easily get 50/1.4 or 100/2 lenses for normal use. It is always easier to achieve sharpness with smaller apertures.

So, there are quite a few reasons, why macro lenses should be sharper than standard lens designs.

Ben
04-13-2011, 01:55 PM   #30
Inactive Account




Join Date: Dec 2008
Location: Ames, Iowa, USA
Photos: Albums
Posts: 2,965
macro maybe sharper for macro...

QuoteOriginally posted by mikknu Quote
.... do macro shots come off as being sharper when compared to shots taken with a telephoto lens?
I just happened to stumble on some optics optics theory/lens design stuff that was discussing some details.

Encyclopedia of Optical Engineering ... - Google Books

It is not an "easy read" but I think I figured out that simple lens theory assumes that light is flat when it enters the lens. This is really only true for subjects really far away but photographers don't take pictures of objects really far away. So lens designers compromise and adjust lenses so that things at a reasonable distance focus best. Sometimes this "reasonable distance" is the hyperfocal distance according to the article.

But I suspect when they make a real lens for macro use they adjust things so focus is best for objects not-so-far away.

Therefore your ultra sharp macro lens may indeed not be too cruel when used for portraits!

I need to check this out in more detail but it sounds reasonable.

Of course some of our regular posters have been saying or implying this all along.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
dg, k-mount, lens, lenses, macro, pentax lens, pictures, shots, sigma, slr lens, telephoto
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are you satisfied with the K-x image quality? rjm Pentax DSLR Discussion 37 01-21-2010 06:27 AM
How can I get good image quality from a K-x?? Manfred Troubleshooting and Beginner Help 38 12-20-2009 08:18 PM
K or M Series - Which has the best image quality 8540tomg Pentax SLR Lens Discussion 20 10-05-2009 07:53 AM
K-7 image quality concern claude21 Pentax DSLR Discussion 31 06-26-2009 11:34 AM
Image Quality - Various Macro Lenses Khukri Pentax SLR Lens Discussion 12 08-23-2007 08:15 PM



All times are GMT -7. The time now is 10:20 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top