Glass Lens Magnifiers | Clarity You Can Trust - magnifing lens

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For most hobbyist photographers leaving a lens cap on all the time vs. simply using a uv filter to protect the lens isn’t efficient. If you need to grab your camera and quickly take a shot, removing the lens cap could mean you miss the shot. I haven’t had a single reason to have a lens cap on a lens that I can think of. If you fall into the purist camp “lenses shouldn’t have filters on them ever” then I could see having a lens cap is better than nothing.

To compare the mean root mean square (RMS) of total higher order aberrations (HOAs), coma and spherical aberrations in individuals with myopia, hypermetropia and myopic astigmatism.

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Thanks for taking the time to read the post and leave a comment. Let me preface what I’m about to say with this: this site is mostly written for newer photographers. You sound like a more experienced shooter so your gear and usage needs may vary greatly from my average reader.

A UV filter helps filter ultraviolet rays from the light coming through your lens. Enough geek-speak for you? Here it is in plain english, UV filters reduces glare. Sun glare off of small waves in a lake, the gleaming sun off the chrome on a motorcycle, the reflective sun off of a glass window in a building. Screw a UV filter onto the front of your lens and you will cut down the gleaming sun.

In order to generate more accurate and reliable results, patients were instructed to stop using contact lenses for at least 02 weeks prior to aberrometry. All patients were examined for Uncorrected visual acuity (UCVA) and corrected distant visual acuity (CDVA) followed by slit lamp examination to rule out conditions like dry eyes, corneal ectasia, corneal scar, cataract, media opacities, previous surgery or trauma. HOAs were measured by aberrometer (Wavelight Allergo Analyzer Version 1073) after instillation of cyclopentoalate (0.5%, 1 drop repeated after 15 mins) to paralyze the accommodation and dilate the pupil. Measurements were repeated three times for each eye and the best image was selected. Analysis was based on a pupil size of 6 mm. RMS value was calculated from Zernike coefficients and we calculated mean RMS of total HOAs, spherical aberrations and coma.

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I’m not sure if lens have asses, but I’ll try my best. I was shooting a wedding with two cameras around my neck and was crouching down to get a shot. One of my cameras with my mid-range zoom slid off my lap to the ground and landed straight onto the lens. The sound of breaking glass will haunt my dreams forever!

Correspondence: Dr. Muhammad Saim Khan, Armed Forces Institute of Ophthalmology, Mall Road, Military Hospital, Rawalpindi, Pakistan. E-mail: saim_amc@hotmail.com

I get “what size filter do I need” question a lot from new photographers so I thought it would be helpful creating a comprehensive list. I see no problem posting affiliate links for a brand and product I’ve personally used for 6 years and have on all my lenses. Not all lenses have the filter size on them. In my gear bag right now I have a 50mm f/1.4 and a 100mm f/2.8 that have no filter size noted anywhere.

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I unscrewed the filter from the lens and keep on shooting! I actually got applause from the attendees of the wedding when this happened!

Shows correlation ‘r’ between SE of refractive error and HOAs in various groups.* indicates statistically significant results.

Higher order aberrations (spherical aberrations, coma, trefoil) are small optical irregularities of the ocular refractive media. Unlike low order aberrations (myopia, hypermetropia, simple astigmatism) they cannot be corrected with spectacles or contact lenses. After successful correction of refractive error by refractive surgery, patients at times complain of halos, glare and decreased contrast. Authors have concluded that HOAs are responsible for these postoperative symptoms.1 Many studies in the past showed significant variability of HOAs among the individuals of same population. Popularization of laser corneal refractive surgery and its potential to induce or remove optical aberrations (both low order and higher order aberrations) is the main reason behind better understanding of the nature of aberrations as well as their influence on visual quality.2 In the normal eye, cornea is responsible for 90% of total aberrations and Zernike polynomials are most commonly used to describe these HOAs. Advent of new diagnostic modalities and introduction of wave front technology has brought revolution in the field of corneal refractive surgery. These advancements has expanded the indications of corneal refractive surgery beyond correcting only low order aberrations.3

In overall comparison we noticed the mean RMS of total HOAs and spherical aberrations were significantly higher in hypermetropia group and there was a statistically significant negative correlation between SE of hypermetropia and RMS of Total HOAs.

A UV lens filter is a disk of coated glass that screws onto the front of your camera lens. If you look close at the front of your lens you will notice there is a thin threading. This is there so you can screw a filter onto the front of your lens. There are a ton of different filters out there. A filter works just like when you put on sunglasses, its puts something between the light and your eye to change it in some way.

May 1, 2023 — Get closer to the subject, concentrate on the area of the subject that you want to be razor-sharp, and use large focal lengths (from 70mm) and ...

Contains a magnifying lens that has a magnification power of 10x. If a microscope has only one ocular lens it is called a monocular and if it has two ocular ...

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This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

You could miss a once-in-a-lifetime photo from those lost few seconds! How many times has this happened to you while wanting to take a quick photo with your phone but your screenlock prevented you from getting it?

I have yet to meet a photographer who has been able to look at a photo and tell the quality of the UV filter from the photo. I can understand you might want the best you can afford if you are a professional photographer, and make your living from delivering images to clients, but 99% of the time the cheap filters are perfectly functional. I’ve personally shot ad campaigns with a $15 UV filter and didn’t have any complaints, color-cast issues, etc. Again, if you have the budget for the best of anything you should likely get it, but considering most of my readers don’t have an infinite budget I feel more comfortable having them put that $50-80 difference toward a better lens, speedlight, etc. that will noticeably impact the quality of their image. Personally I’ve never bought the “buy expensive filters because thats what you’re supposed to do” ethos.

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Aberrometry has proven to be invaluable in detecting eyes with an abnormal optical conditions especially in the context of corneal refractive surgery. Wavefront aberrations differed widely among the subjects, with a mean SD of approximately 0.10 um for RMS of Total HOAs. The summary of optical quality can be deduced from aberration coefficient and described as RMS value in micrometers. In our study, we investigated ocular HOAs in patients with myopia, hyperopia and astigmatism. The main focus was on coma (third order aberrations) and spherical aberrations (forth order aberrations), as these were the most significant components of HOAs.13-16 Authors have concluded the mean RMS of Total HOAs to be 0.33um for a 6.0-mm pupil.5,17-20

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This prospective analytical study was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan from Jan 2014 to Dec 2014. Sample size was calculated on the basis of WHO calculator and appeared to be 200 eyes. So a total of 200 eyes of 121 subjects were included in the study by non-probability (consecutive) sampling technique and two eyes of the same patient were considered independently. Most of the patients were evaluated to undergo refractive surgery. Included were the patients with age ranging from 18 – 40 years and refractive error more than ± 0.5 D, while those with history of ocular disease and amblyopia were excluded. We categorized the patients into four groups on the basis of mean spherical equivalent (Table-I).

The $10 UV filter screwed onto the front for the previous year and a half shattered. Imagine losing one of your go-to lenses in the middle of shooting a live wedding! I thought lost the lens but realized that only the filter was shattered.

Each lens has a filter size. Most of the time, the lens will have the number for the size filter it needs on the front of the lens. Its a number next to a circle with a line through it. Use that number when looking up the lens filter size.

This prospective analytical study was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan from Jan 2014 to Dec 2014. Two hundred eyes of 121 patients with age ranging from 18-40 years were included in the study. Patients were divided into 4 group namely Low myopia, High myopia, Astigmatism and Hypermetropia on the basis of refractive error. Included were the patients who had refractive error more than ± 0.5D and best corrected visual acuity (BCVA) of 0.00 or better. Patients who had history of surgery and / or eye disease were excluded from the study. Visual acuity (VA), Spherical equivalent (SE) of refractive error, RMS value of total HOAs, coma and spherical aberrations were evaluated. HOAs were measured with aberrometer (Wavelight analyzer version 1073) at 6 mm pupil size.

In our study, we found that HOAs were lower in myopes when compared to hypermetropes (Table-II). However this can be due to significantly higher mean age in hypermetropic group than myopes (Table-I) and studies have shown that HOAs increase with age.5,17-19 Marcos et al,10 reported that RMS of wavefront aberrations in high myopia (>6.0 D) has statistically significant positive correlation with refractive error. We in our study found out that there was no significant correlation of HOAs with amount of refractive error in all the groups except in hypermetropes. We, like He J et al.9 also found out no significant relation of myopic error with HOAs in contrary to Marcos et al. who conclude a positive correlation between the two (Table-III). Patients in hypermetropia group had statistically significant higher amount of spherical aberrations than other three groups as reported by Lorente et al.20 and Bisneto et al.21 We also found out a statistically significant negative correlation `r` of Hypermetropia with RMS of Total HOAs and Spherical aberration (marked with * in Table-III).

Spherical aberration

I’ve seen a lot of new photographers carting their camera around with a lens cap on all the time. I did the same thing when I started out. This is a pain in the ass because you can never take the lens cap off quick enough when something is happening and you end up missing the shot.

I see a lot of new photographys carrying their cameras around with the lens cap on all the time. These are easy to lose, and kill any spontaneous photography you could ever hope for. Something starts happening and you are busy fumbling with the lens cap!

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Statistical package for Social sciences (SPSS 17.0) for windows was used for statistical analysis. The data was described in terms of mean±SD (Standard deviation) for each group on the basis of type of refractive error. Linear regression analysis was used to assess the distributions of HOAs (total HOAs, coma, spherical aberration)and their correlation with amount and type of refractive error.(p<0.05 significance level)

Zernike polynomials are divided into several orders, low-order aberrations (first and second order), and high order aberrartions (third order onwards). Important higher order aberrations include coma, trefoil and spherical aberrations and they are measured by root mean square (RMS) value which represents the ocular aberrations in micrometers. Values of measured ocular aberrations in the Zernike polynomials are dependent on pupil diameter at the time of examination.2-4 HOAs and their relation to amount and type of refractive errors has been studied in a number of studies but the result are controversial. Some studies have shown no statistically significant correlation between HOAs and amount or type of refractive error,5-7 while others concluded a strong correlation of HOAs with myopia.8-11 Spherical aberrations were found significantly correlated with myopia by some authors,8 while others confined their relation to high myopia only,12 and still others could not found any statistically significant correlation.11

Good point, I should add Sony to this list. I wrote this post a few years ago before Sony exploded onto the scene and stepped their game up! Thank you for bringing this to my attention.

A *good* UV filter that you’d actually want to put on, say that $1600 85 f/1.4 you have on your list, will cost you around $70. If/when you do decide to buy a filter, finding the size you need isn’t a pain. It’s clearly labeled on the front of most lenses. Look for the circle with a line through it.

The rationale of conducting this study was to collect a local database of HOAs among various refractive errors in patients investigated for refractive surgery. The comparison of HAOs (in micrometers) with the amount and type of refractive error (in diopters) will help in management of these patients.

Age of the patients ranged from 18 years to 40 years with mean age of 29.10±10.6 years. Seventy one (35.5%) were males and 129 (64.5%) were female. Mean RMS value of HOAs, coma and spherical aberrations was calculated in all four groups. RMS of total HOAs and spherical aberrations in hypermetropia was 0.96±0.96 and 0.30±0.42 respectively and it was higher than other three groups.

In overall comparison the mean RMS of total HOAs and spherical aberrations was significantly increased in hypermetropia group and there was a statistically significant negative correlation of SE of hypermetropia with RMS of total HOAs and spherical aberration.

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The real practicality of a UV filter is that protects your lens just like your lens cap. That means as long as you have a UV filter on the front of the lens, you don’t need to bring your lens cap! Any scratches, dirt, dust, or damage will happen to the UV filter and not your lens! I never leave home without one of these on my camera.

A total of 200 eyes of 121 patients were studied. Seventy one (35.5%) were males and one hundred and twenty nine (64.5%) were females. Age of the subjects ranged from 20 to 40 years with mean age of 29.1±10.6 years. Mean age of hypermetropes was 32.3±8.33 while other three groups were 23.5±3.5, 24.5±3.0, 23.5±3.0 for low myopia, high myopia and astigmatism respectively. Refractive error was described in terms of spherical equivalent and it ranged from +6.00 to - 10.50 D. RMS of total HAOs, spherical aberrations and coma were calculated and given in Table-II. The distribution of various HOAs across the range of refractive error is given in scatter graphs. (Fig. 1, 2 & 3). Correlation of SE of refractive error and various HOAs was analyzed and statistically significant is marked as * in Table-III.

Yes, a lens filter is a good idea. But encouraging people to adopt bad habits so you can have a page full of affiliate links isn’t a hack. If you can’t remove a lens cap, you need to practice removing a lens cap.

Thanks for taking the time to read the post and leave a comment. Let me preface what I’m about to say with this: this site is mostly written for newer photographers. You sounds like a more experienced shooter so your gear and usage needs may vary greatly from my average reader.

Some authors have concluded HOAs to be more in ametropia than emmetropic eyes9 while others proposed no relationship or even an opposite relationship between refractive error and HOAs8,12,22 and still others reporting greater higher order aberrations in myopes compared to hyperopes.23 Amount HOAs in our study were comparable to Chinese population however, we found our results to be higher when compared to Caucasians.6,24,25 The currently available literature regarding the clinical importance of HOAs and the potential benefit of correcting them made us study HOAs in our population. We believe that our results are important but studies on larger sample size are required to further evaluate, analyze and compare not only the changes in HOAs with refractive error but also their effect on patients` quality of vision.

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